Physics and Chemistry S E C O N D A R Y 3 This book is a collective work , conceived, designed and created by the Editorial depar tment at Santillana , under the super vision of Teresa Grence. WRITERS María del Carmen Vidal Rosalie Wheeler EDITORS Bárbara Braña Heather Sutton Dave Wile EDITORIAL MANAGERS Nuria Corredera David Sánchez PROJECT DIRECTOR Antonio Brandi BILINGUAL PROJECT DIRECTOR Margarita España Do not write in this book. Do all the activities in your notebook.
Contents Uni t Learning s i tuat i on C H A L L E N G E Susta inabl e Deve l opment Goa l s (SDG ) and the i r target s 1 Science and measurement 8 Record a video tutorial on the scientific method Sustainable Development Goals 2 Gases 34 Organise a science fair at your school SDG 4: Quality education Target 4.1 3 Mixtures 56 Help to say no to alcohol SDG 3: Good health and well-being Target 3.5 4 The atom 82 Write the screenplay for a radioactive series SDG 12: Responsible consumption and production Target 12.4 5 Elements and compounds 108 Design an app about the periodic table SDG 12: Responsible consumption and production Target 12.2 6 Chemical reactions 130 Fight fires and climate change SDG 15: Life on land Target 15.2
Essent i a l knowl edge Sc i ent i f i c work Cr i t i ca l think ing 1. Experimental sciences 2. The scientific method 3. Scientific method application 4. Technological applications of scientific research 5. Measurement 6. Laboratory work - Handling solids - Handling liquids - Weighing substances - Measuring volumes - Investigate the relationship between the mass and the volume of an object Is astrology a science? 1. The study of gases 2. Atmospheric pressure 3. Gas laws. The Boyle-Mariotte law 4. Gas laws. Gay-Lussac's law 5. Gas laws. Charles's law 6. The general ideal gas equation 7. The kinetic theory of gases - Relate atmospheric pressure and the Boyle-Mariotte law - Prove the Boyle-Mariotte law with an experiment - Relate atmospheric pressure and Gay-Lussac's law - Relate atmospheric pressure and Charles's law - Prove Charles's law with an experiment Can air enter the blood if the liquid in a drip runs out? 1. Diversity of matter. Pure substances and mixtures 2. Solutions 3. The concentration of solutions 4. The solubility of substances 5. Colloids 6. Separation of the components of a mixture - Prepare a saline solution - Prepare 250 mL of a solution of salt in water with a concentration of 40 g/L - Making a paper filter - Extracting the dye from red cabbage - Separate a liquid from a dissolved solid by distillation - Separate alcohol from a mixture by distillation - Perform an ink chromatography Can we trick a breathalyser? 1. Atomic models. What are atoms like? 2. The particles that make up atoms 3. Advances in the atomic model 4. How atoms are represented 5. Isotopes 6. Atomic mass 7. Atoms and electricity 8. Ions: anions and cations 9. Radioactivity - Identify chemical elements by the colour of a flame Are microwave ovens radioactive? 1. History of the elements 2. The periodic table of elements 3. The most common chemical elements 4. How matter is arranged 5. The most common chemical compounds - Analyse the elements used in a mobile phone - Separate the elements of a compound Is the calcium in milk better than the calcium in other foods? 1. Chemical reactions 2. How a chemical reaction happens 3. Chemical equations 4. Calculations in chemical reactions 5. Important chemical reactions 6. Chemistry and the environment 7. Medicines and drugs 8. Chemistry and progress - Study the oxidation reaction of magnesium - Study the reaction between vinegar and bicarbonate - Study the reaction between HCℓ and NH3 - Dissolve an eggshell - Study the reaction between iron and a copper(II) sulphate solution Are alcohol and tobacco drugs?
Contents Uni t Learning s i tuat i on C H A L L E N G E Susta inabl e Deve l opment Goa l s (SDG ) and the i r target s 7 Forces and machines 158 Design machines that help other people SDG 10: Reduced inequalities Target 10.2 8 Motion 180 Design a campaign to improve road safety where you live SDG 3: Good health and well-being Target 3.6 9 The forces of nature 212 Develop models to explain the forces of nature SDG 4: Quality education Target 4.1 10 Electricity and electronics 240 Propose actions to reduce electronic waste SDG 12: Responsible consumption and production Target 12.5 11 Electrical energy 266 Develop proposals for renewing electric power stations SDG 13: Climate action Target 13.3 Annexes 288
Essent i a l knowl edge Sc i ent i f i c work Cr i t i ca l think ing 1. What is a force? 2. Forces and deformation 3. The action of several forces 4. Forces around us 5. Machines and forces - Find the relationship between force and the stretching of a spring - Determine the constant k of a spring - Study the force that must be applied to an object so that it is in equilibrium Does the frictional force of a car affect pollution? 1. Speed 2. Uniform rectilinear motion (URM) 3. Acceleration. Motion with acceleration: UARM 4. Uniform circular motion (UCM) 5. Forces and motion. Newton's laws. - Calculate the velocity of a movement from a graph - Calculate acceleration from a speed–time graph - Measure the average speed in UARM Do cyclists have priority at pedestrian crossings? 1. The movement of celestial bodies 2. Gravity: the force that makes celestial bodies move 3. The Universe 4. Revolution and rotation 5. Electric charge and electric force 6. Magnetism 7. Relationship between electricity and magnetism 8. Nuclear forces - Use an electroscope or a versorium to detect an electric charge - Carry out Ørsted ’s experiment - Check the functioning of an electromagnet - Generate an electric current with a magnet 1. Electric current 2. Electric circuits 3. Electrical quantities 4. Ohm's law 5. Electric circuit calculations 6. Using electric current 7. Applications of electric current 8. Electronics - Relate the intensity, voltage and resistance of a component - Analyse the applications of electronics in a mobile phone Can a few batteries contaminate all the water in an Olympic-sized swimming pool? 1. Electric current generators 2. Electric power stations 3. Transportation and distribution of electricity 4. Electricity production and consumption 5. Environmental impact of electrical energy 6. Electricity at home - Analyse how an alternating current generator works Things people say about energy… Formulas of inorganic compounds Periodic table of elements
Education is a long road that lasts a lifetime. Follow the WORLD MAKERS learning path to create a more equal, fair and sustainable world. Learning path The atom 4 L E T ' S G E T S TA R T E D Write the screenplay for a radioactive series L E A R N I N G S I T UAT I O N Chernobyl nuclear power station , Ukraine, April 1986. During a test, an accident caused one of the nuclear reactors to explode. An endless number of radioactive particles polluted the atmosphere, water, vegetation , animals and the people living nearby. Humans will not be able to inhabit this region again for many years. In 2019, a TV series about this accident was released . Would you like to write the screenplay of a series where nuclear energy has the leading role? In this unit we will help you to do it. Take act ion As you write the screenplay for the series, you will learn about radioactivity and some of its applications. You will study the characteristics of radioactive waste and how it must be managed to achieve this target of the SDGs. Target 12.4: "By 2030, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle […] and significantly reduce their release to air, water and soil in order to minimise their adverse impacts on human health and the environment." What is an atom? What particles form atoms? What is the relationship between atoms and electricity? What is nuclear energy? What other types of energy do you know? Describe them. WORK WITH THE IMAGE Look at the photo on the previous page. In 2016, a massive 30 000-tonne steel structure was constructed to cover the remains of the Chernobyl nuclear reactor. It cost 1.5 billion (1 500 000 000) euros. Why was it built, if it has been several decades since the accident? The structure was assembled in a separate place. Then it was taken to its final location and placed over the reactors. What could be the reason for this? Why do you think steel was used instead of wood or aluminium to cover the reactor? Look at the photo on the left. Why do people who work with radioactive waste wear special suits? IN THIS UNIT… Atoms. Atomic models The particles that make up atoms Advances in the atomic model Atoms, isotopes and atomic mass Atoms and electricity Ions: anions and cations Radioactivity CHALLE NGE 83 82 ES0000000137418 183391_Unidad04_111062.indd 82-83 18/7/22 13:30 WHAT IS MATTER MADE UP OF? Ever ything around us is made up of atoms. ATOMS AND ELECTRICITY Certain materials become electrically charged when rubbed together. Two types of forces appear between them. RADIANT ENERGY Radiant energy is the energy in electromagnetic radiation . When an object is rubbed , its atoms can gain or lose electrons and acquire a negative or positive electric charge, respectively. PHYSICS AND CHEMISTRY REVISION 1 Classify the particles that make up the atom according to whether they are in the nucleus or shell. 2 Look at the energy diagram and the types of electromagnetic radiation. Describe an application or device that is used regularly for each type. 3 Do an experiment to test whether various materials become electrically charged when rubbed together. Rub a plastic pen on your jumper and attract small pieces of paper with it. Then rub it with something made of cotton. Now do the same with a wooden pencil instead of the plastic pen. A C T I V I T I E S + Proton : particle with a positive electric charge Neutron : particle with no electric charge - Electron : particle with a negative electric charge Repulsion Attraction Two pieces of electrically charged glass repel . Two pieces of electrically charged amber repel . Electrically charged glass and amber attract. ENERGY Radio waves Microwaves Infrared Visible Ultraviolet X-rays c rays 2 oxygen atoms 2 nitrogen atoms Silicon atoms 2 hydrogen atoms and 1 oxygen atom Carbon atoms Aluminium atoms Shell Nucleus STRUCTURE OF AN ATOM 84 ES0000000137418 183391_Unidad04_111062.indd 84 18/7/22 13:33 Mass Electric charge Proton 1 u +1 e Electron 1 / 1 836 u -1 e Neutron 1 u 0 3 10 Calculate how many protons we need for the total mass to be 1 kg. And neutrons? And electrons? 11 Calculate how many protons we need for the total electric charge to be 1 C. And electrons? A C T I V I T I E S 2.2. The atomic scale As protons, neutrons and electrons are ver y small particles, when working with atoms, it is common to use the atomic scale. This uses the approximate mass and charge of a proton as units of mass and charge. S O LV E D P R O B L E M 1 Calculate the mass and charge of the atom in the image. Write the result in SI units and in the atomic scale. 1. Count the particles of each type in the atom. Protons: 2 Neutrons: 3 Electrons: 2 2. Find the mass and charge data of each particle. Make a table with the number of particles and the mass and charge calculations of each particle type in SI units. Then calculate it for the whole atom. Particles Number Mass (kg) Charge (C) Proton 2 2 ? 1.673 ? 10-27 = 3.346 ? 10-27 2 ? (+1.6 ? 10-19) = +3.2 ? 10-19 Neutron 3 3 ? 1.675 ? 10-27 = 5.025 ? 10-27 3 ? 0 = 0 Electron 2 2 ? 9.11 ? 10-31 = 1.822 ? 10-30 2 ? (-1.6 ? 10-19) = -3.2 ? 10-19 Total for the atom 8.373 ? 10-27 0 The mass of the atom is 8.373 ? 10-27 kg and its charge is 0 C. 3. Repeat the previous step using atomic units. Particles Number Mass (u) Charge (e) Proton 2 2 ? 1 = 2 2 ? (+1) = +2 Neutron 3 3 ? 1 = 3 3 ? 0 = 0 Electron 2 2 ? 0* = 0 2 ? (-1) = -2 Total for the atom 5 0 The mass of the atom is 5 u and its charge is 0 e. unit of atomic mass (u): unit of atomic charge (e): 1 u = 1.66 ? 10-27 kg 1 e = 1.6 ? 10-19 C * In units of atomic mass, we can consider the mass of the electron to be zero. 87 ES0000000137418 183391_Unidad04_111062.indd 87 18/7/22 13:34 LEARNING SITUATION. THE CHALLENGE 1 THE SUSTAINABLE DEVELOPMENT GOALS 2 CORE SKILLS 3 Remember what you already know about the topic, your previous knowledge acquired in previous years, in other units or in your own daily life. Think about an everyday life situation and put yourself in the place of the characters who present it. Contribute to the achievement of one or several targets of the Sustainable Development Goals (SDGs). Analyse examples of SOLVED PROBLEMS, then apply what you have learnt to solve the activities. Think and express your analytical side by doing the different ACTIVITIES. Critical thinking. Discuss whether the information is true or not. In the TRUE OR FALSE? section, you will find suggestions for learning how to create truthful content and for deconstructing fake news and myths. Review in the initial REVISION section what you already know and relate this knowledge to what you are going to learn. Research, think and then answer the questions that will help you complete the challenge and acquire core skills. 3. Advances in the atomic model 12 Why do we get different coloured flames when we burn substances made up of different chemical elements? What is the atomic model that explains this behaviour of atoms? 13 Which is greater, the amount of energy emitted when an electron changes level in an atom, or the energy emitted by an atom of a radioactive element? Identify chemical elements by the colour of a flame An atom is so small that it is impossible to see it directly. One way of detecting the presence of atoms of a certain chemical element is to do a flame test. Beaker of water Spatulas Substances to analyse Glass rods Containers, spatulas and glass rods Flammable alcohol (methanol or ethanol) Long-handled lighter Substances to analyse: – Sodium carbonate, Na2CO3 – Copper dichloride, CuCl2 – Potassium bromide, KBr 1. Put some of the substance you are going to analyse into a clean crucible with the tip of a spatula. 2. Add between 3 and 5 mL of alcohol and stir it with the glass rod. 3. Light the flame of the lighter at the edge of the crucible. 4. Observe the colour of the flame. At first it will be blue, because of the alcohol. Then it will change. Stir it from time to time with the glass rod to revive the flame. 5. Wait for the flame to go out, or put it out with water. 6. Search for information about the flame test and identify which chemical element corresponds to the colour of each flame. Steps Sodium carbonate Copper dichloride Potassium bromide All the materials must be very clean, so that products are not contaminated with other products. Be careful not to spill alcohol onto the table. If any alcohol is spilt, clean it well before lighting a flame. If you perform more than one analysis at a time, make sure that the crucibles are far away from each other, so that the flames do not touch. Have a large beaker of water ready in case flames from the crucibles get out of control. Crucibles Materials CHALLENGE 88 ES0000000137418 183391_Unidad04_111062.indd 88 18/7/22 13:49 3 Are microwave ovens radioactive? The energy of the microwaves makes the water molecules inside the food vibrate, which generates heat and cooks the food . Microwaves are ref lected by the metallic parts inside so that they spread in all directions and reach the food . Microwave ovens generate electromagnetic radiation , similar to a mobile phone, a radio, or sunlight. Microwave ovens are not radioactive! 48 Spain pays around 75 000 € per day to France for storing our nuclear waste. However, some Spanish nuclear power stations have their own pools to store waste. a) What type of waste is collected in the pools in nuclear power stations: very low, low, medium or high level? b) Investigate how that high daily payment for storing nuclear waste could be avoided. 49 Hospital radiology departments often employ people with a knowledge of nuclear physics or chemistry. a) Why do you think these people work there even though they have not studied Medicine? What do you think their job involves? b) What precautions should be observed in a hospital where radioactive isotopes are used in the diagnosis or treatment of diseases? A C T I V I T I E S This is not harmful to living things, but it can sometimes cause interference with other types of radiation , such as a wi-fi network. Unlike a mobile phone, in a microwave oven the waves are concentrated in an enclosed space. The ovens emit low levels of microwave radiation , although they are protected . T R U E OR FALSE ? RESTRICTED ACCESS RISK OF RADIATION 101 ES0000000137418 183391_Unidad04_111062.indd 101 18/7/22 13:34 Do experiments and carry out simple practical activities. Complete the steps by applying what you have learnt. Acquire essential knowledge from content explained in a very clear way and with strong visual support: photos, drawings, diagrams, etc. Mass 9.11 ? 10-31 kg Charge -1.6 ? 10-19 C Electron Mass 1.675 ? 10-27 kg Charge 0 Neutron Mass 1.673 ? 10-27 kg Charge +1.6 ? 10-19 C Proton The unit for electric charge in the SI is the coulomb (C). 2. The particles that make up atoms 7 What mass do the particles that make up atoms have? Which have a greater mass? 8 Are these particles electrically charged? How can atoms be neutral? 9 Do you think that the size of the particles in the atom made it difficult to study nuclear energy, compared to other sources of energy, such as wind or water energy? Why? By comparing the mass of the proton and the electron , we obtain : . . ? ? m m 9 11 10 1 673 10 1836 kg kg electron proton 31 27 = = - - " mproton = 1 836 ? melectron The mass of the proton is 1836 times greater than the mass of the electron , just as the mass of a giraf fe is about 1 836 times greater than that of a guinea pig. The mass of the proton is ver y similar to that of the neutron . The mass of the electron is much less than that of the proton and neutron . The charge of the electron is the same as the charge of the proton , but with the opposite sign . The atom is neutral , so it must have the same number of protons as electrons. The number of neutrons is similar to the number of protons, but it does not have to be the same. CHALLENGE All the matter around us is made up of atoms. 2.1. Properties of the particles that make up atoms In 1932, it was discovered that in the nucleus of atoms there is a particle that has no electric charge. It was called the neutron. Various investigations enabled us to know the mass and electric charge of the particles present in the atom. 86 ES0000000137418 183391_Unidad04_111062.indd 86 18/7/22 13:33 ESSENTIAL KNOWLEDGE 4
With the STUDY NOTES you can revise the key concepts of each unit and check your progress. C O N C E P T M A P > Copy and complete the concept map. particles … : negatively charged protons: … charged … : not charged S U M M A R Y representation definition types of radiation the nucleus of an … atom decays and emits very … radiation ATOM ATOMIC MODELS RADIOACTIVITY A Z X isotopes A: … X: symbol of the element Z: atomic number Dalton (1803) … reactions fission: nuclei break apart … : nuclei join together … (1904) Rutherford (1909) … (1913) indivisible particles: … positively charged sphere with … charged electrons … in the nucleus and electrons orbiting it … model electrons move around the nucleus in orbits, layers or … levels … model ions atoms with the same number of … and a different number of … atom loses electrons atom gains electrons positive ion or … negative ion or … … particles ß particles X-rays … rays … 19 4 ES0000000149816 223258_Unidad04_112065.indd 19 18/7/22 13:37 o r g a n i s e yo u r i d e a s 3 c h e c k yo u r p r o g r e s s 50 TA B L E . Complete the table in your notebook by putting the data below in the correct boxes. Proton Electron Neutron Mass 1.673 · 10–27 kg ... ... Charge ... ... ... -1.6 ? 10-19 C +1.6 ? 10-19 C 0 C 9.11 ? 10-31 kg 1.675 ? 10-27 kg Then complete another table like the one above. Indicate the value of the mass and the charge in atomic units. 51 D R AW I N G . The diagrams below represent the two atomic models that we studied in this unit. Draw and label them in your notebook. Shell Layers model Proton Electron Layer Neutron Nucleus Planetary model 52 D I A G R A M . We use the symbol A ZX to represent an atom. Complete the diagram in your notebook. 235 92U ... ... ... Then complete these sentences. a) The number of protons is given by … . b) The number of electrons is given by … . c) The number of neutrons is given by … . 53 D I A G R A M Complete this diagram comparing the two isotopes of copper, 63Cu and 65Cu, in your notebook. 65Cu 63Cu ... ... Z ... ... A ... ... No. of neutrons ... ... No. of protons ... ... No. of electrons 54 D I A G R A M Complete this diagram in your notebook. It gains electrons ... ... ... ... Cation Atom 55 DIAGRAM Compare nuclear fission and nuclear fusion and write the differences between them in your notebook. ... Fusion ... ... ... Fission ... ... Definition Energy generation Waste generated What atoms are like 56 St. Peter’s Basilica in Rome is the largest temple in Christianity. Its dome has an internal diameter of approximately 40 m. Imagine an atom the size of this dome. Which of these objects are comparable in size to its nucleus? 57 Analyse these sentences. Write in your notebook the one that explains why we say that most of an atom is empty. a) Electrons are much smaller than protons. b) The nucleus of an atom is much smaller than the atom. c) Atoms are very small structures. 58 What mass will a sodium (Na) atom have if it is made up of 11 protons, 12 neutrons and 11 electrons? 59 Look at the diagrams of these atoms and complete the table below: Atom Number of layers Number of electrons per layer Total number of electrons O ... ... ... Na ... ... ... P ... ... ... S ... ... ... 60 Draw the layers model of an atom of these elements: nitrogen, aluminium, calcium and neon. 61 An atom has 53 protons and 74 neutrons. a) What is its atomic number? And its mass number? b) Use the periodic table in the annex to find which chemical element it belongs to. What is its symbol? 62 Draw a diagram of these atoms. Show all the particles and where they are located. a) 14 6 C b) 14 7 N 63 Analyse the drawings below that represent these atoms and complete the diagram in your notebook. Beryllium Boron B Be ... ... No. of electrons ... ... No. of neutrons ... ... Atomic number: Z ... ... Mass number: A ... ... No. of protons Lithium Helium S O LV E D P R O B L E M 3 Draw a diagram of these atoms, showing all the particles and where they are located. 4 2He 7 3Li 1. Identify the particles in each atom. Remember what A ZX means. X: name Z: no. of protons No. of electrons A - Z: no. of neutrons Helium 2 2 4 - 2 = 2 Lithium 3 3 7 - 3 = 4 2. Draw the atoms: a) In the nucleus, draw the protons (in red) and the neutrons (in green). b) In the shell, in layers, draw the electrons (in blue). Keep in mind the number of electrons that can be in each layer. Place the third electron in the second layer, as only two electrons fit in the first layer. Model: ... C A B E D Model: ... C A B E D Sulphur (S) Oxygen (O) Sodium (Na) Phosphorus (P) Basketball (24 cm diameter) Ping pong ball (4 cm diameter) Pearl (4 mm diameter) Use the STUDY NOTES to review the content of this unit. 103 102 ES0000000137418 183391_Unidad04_111062.indd 102-103 18/7/22 13:32 Ac t iv it y wr i s tbands Few people could have predicted the success of these devices a few years ago. Is there any athlete who does not have a smart watch or wristband now? The beginnings were not at all easy. Fitbit only had two employees during its first three years and failed to make a profit until the fourth year. “On the day of the demo, when we launched the first product, someone asked me how many people had reserved one. I replied there were only five people. I was told that was quite pessimistic,” Fitbit CEO James Park remembers. www.itespresso.es (Adapted) In 2007 the first activity wristband was released by the company Fitbit. Activity wristbands are fitted with various sensors. These allow the wristband to collect dif ferent types of data . Then this is processed to give you appropriate suggestions through an app. ▶ How do wristbands count steps? Most wristbands include sensors called accelerometers that can measure movement. Normally, accelerometers have three axes that allow them to sense movement in all directions. ▶ How do wristbands measure height? An altimeter sensor determines the height of a mountain you have climbed . This sensor tells you how many steps you have climbed up or down in a day. ▶ How do wristbands know how I sleep? They use sensors that can track wrist movements. When we sleep, the horizontal position of the body is interpreted as the initial stage of sleep. Our heart rate slows down , blood pressure decreases, muscles relax and we move less. The activity wristband can also detect the drop in heart rate and the lack of wrist movement. ▶ How do wristbands measure my pulse? There are two methods: • Optical sensors. They use sensors that emit continuous beams of light that dif fuse into the skin , lighting up the blood vessels. At the same time, another sensor detects the speed at which blood is pumped by the heart. This system is especially useful when we exercise and our heart rate is ver y easy to detect. • Bioimpedance sensors. They emit electrical impulses that detect the resistance of the skin to these impulses. This resistance is interrupted ever y time the heart beats. This is how the sensor can measure the pulse rate. ▶ How do wristbands measure calories? They use the data collected by the dif ferent motion and temperature sensors. This tells the wristband how many steps we have taken in a day, how many steps we have climbed up or down, and how far we have travelled. Using algorithms, this information is then compared with data previously entered into the wristband, such as weight, height, sex and age. The result is shown as the amount of calories burnt in a day. pulseradeactividad .net (Adapted) > Find information and explain what features a GPS sensor adds to activity wristbands. 4 228729_Innovations Part 1.indd 4 18/7/22 16:07 FINAL ACTIVITIES 5 Study the information and apply your essential knowledge to different contexts and situations. Do the activities in the ORGANISE YOUR IDEAS and CHECK YOUR PROGRESS sections. Critical thinking. Analyse a news article and answer the questions that will help you to think about and show your reasoning. Make connections between Physics and Chemistry and other subject areas to help you understand the world you live in. Complete the challenge and tell other people what you have achieved. Share the results with the people around you. In this way, you are contributing to the construction of a better world for everyone. 76 Nuclear power is said to be a clean energy. What does this mean? Is nuclear waste not a pollutant? 77 The technical staff that do X-rays on patients leave the room just before taking the image. a) Why do you think they do this? b) Could the X-ray machine be kept in a cubicle with wooden walls? 78 Atoms for Peace is the name of a famous conference that was a very important moment in the development of nuclear energy. Form a team and find information to prepare a presentation that shows: a) Who proposed Atoms for Peace? When and where did this happen? b) Before that date, nuclear energy had been used for non-peaceful purposes. What were they? What consequences did they have? c) Make a list of the peaceful uses of nuclear energy. For each one, prepare a summary with their most important applications. 79 Read this article and answer the questions. Nobel Prize winner Gérard Mourou believes that nuclear waste could be made safe in 20 years French Nobel Prize in Physics winner Gérard Mourou , who is working on the development of the most powerful laser in the world , has calculated […] that this application could be used to decontaminate nuclear waste in 20 years. The current experiments with the so-called "extreme light", led by European laboratories, will be able to complete the first tests in this particular application within five or ten years from now. Then it will take ten more years to build the appropriate plants for the treatment of nuclear waste. For the "transmutation" of nuclear waste (removal of radioactivity), this advanced laser will be able to make particles like neutrons more compact "to shorten their harmful lifetime" and reduce the radioactive period from millions of years to just years. This would solve the problem of nuclear energy : the lifetime of toxic waste […]. ecodiario.eleconomista .es 25th May 2019 (Adapted) a) Explain the expression: "to shorten their harmful lifetime". b) Why does the article say "solve the problem of nuclear energy"? What is this problem? c) Can you think of any other areas that could benefit from the technique described in the article? Discuss it in class and write down your conclusions. c h e c k yo u r p r o g r e s s 75 C H E M I S T R Y A N D A R C H A E O L O G Y. Carbon-14 dating is a technique used in archaeology to determine the age of the remains found in excavations. It is based on the decay of C-14 isotopes. C is one of the most abundant elements in living things. While an organism is alive and feeding, the percentage of C-14 in its atoms remains constant. However, when an organism dies, this isotope decays. It is not replaced, so it gradually disappears. It has been observed that every 5 730 years, half of the C-14 atoms in a sample decay and disappear. This period is known as the half-life. a) Assuming that in a sample we have 160 C-14 atoms, calculate how many years it would take to have ten C-14 atoms left. b) Would the C-14 dating technique be useful to determine the age of the remains found in Sima de los Huesos in Burgos, which are about 400 000 years old? Tip: for every 100 C-14 atoms that were present initially, calculate whether there is a significant number of atoms left to analyse the radiation they emit. c) The oldest known rocks have been found in Jack Hills, Australia, and are about 4 billion (4 000 000 000) years old. Would C-14 dating be useful in determining their age with any precision? 106 ES0000000137418 183391_Unidad04_111062.indd 106 18/7/22 13:35 69 Look at the diagrams and identify the atoms and ions they represent. Write their names in your notebook. B A 70 Find the information you need in the periodic table in the annex to complete these sentences in your notebook. a) The symbol for the element chromium is … . The atomic number of chromium is … . This means that all chromium atoms have … protons and, if they are electrically neutral, … electrons. When a chromium atom loses three electrons it acquires a … electrical charge. The chromium atom has become a … ion, or … , and is called a … . b) The symbol for the element sulphur is … . The atomic number of sulphur is … . This means that all sulphur atoms have … protons and, if they are electrically neutral, … electrons. In many compounds, the sulphur atom has 18 electrons. This means it acquires an electric charge of … . The sulphur atom has become a … ion, or … , and is called a … . 71 Complete the table in your notebook. Find the information you need in the periodic table in the annex. Symbol Name P E N Charge A ... Bromide ... ... ... ... B 138 56 Ba 2+ ... ... ... ... ... C ... ... 7 ... 7 3D 83 36 Kr ... ... ... ... ... E 88 38 Sr 2+ ... ... ... ... ... F ... ... 33 ... 75 372 The atomic models you have studied were proposed by men. Today, the role of women in science is just as relevant, as proved by Fabiola Gianotti, the first woman to lead CERN (European Organisation for Nuclear Research), for example. a) Do you think it is important that there are women in charge of scientific institutions? Why? b) Why do you think that most of the discoveries about the structure of atoms were made by men? Radioactivity 73 What type or types of nuclear radiation correspond to each of these characteristics? a) They are electromagnetic radiation. b) They are particles. c) The particles have a mass of 4 u. d) Its electric charge is negative. e) They are particles without a charge. f) It can go through the human body. g) It can go through a lead wall. 74 Which sentences can be applied to the process of nuclear fusion? Which can be applied to nuclear fission? Which are false? Explain in your notebook. a) The particles in the atomic nucleus are broken apart and a large amount of energy is released. b) The particles in the atomic nucleus join together and energy is released. c) The nucleus of the atom is broken into several fragments, releasing a large amount of energy. d) The nuclei of several atoms join together, releasing a large amount of energy. e) The atoms of one element are transformed into atoms of a different element. f) Waste is produced that is very dangerous to our health. 3 J. J. Thomson E. Rutherford F. Gianotti 105 ES0000000137418 183391_Unidad04_111062.indd 105 18/7/22 13:34 80 Prepare a report. Marie Curie received two Nobel prizes: one in Chemistry and one in Physics. Working in pairs, search for information. Highlight her research on radioactivity and the discovery of some chemical elements. Make a poster, report or presentation with your conclusions. 81 Why is radioactive waste dangerous? Choose the correct answer and write it in your notebook. a) Because it is very difficult to recycle it. b) Because it can remain inactive for many years until it starts to emit radiation. c) Because it can emit harmful radiation for hundreds or thousands of years. 82 Ida Noddack and Lise Meitner played an important role in the discovery of nuclear fission. Work in pairs and look for information about these two scientists. Make a presentation that shows: a) The biographical data of each scientist. b) The areas they investigated, as well as their most important findings. c) Their studies on nuclear fission. d) Who received the Nobel Prize for research on nuclear fission. Our first radioactive series Work with your classmates to create the screenplay for your series. Collect some useful diagrams and animations that can be the scientific basis for the screenplay. Draw sketches to represent some key scenes from the start, middle and end of the series. Think: what kind of music would go well with the series? Fast? Calm? Design a poster to promote the series. In the poster, refer to the different atomic models you have studied. Create a #hashtag or tag to promote your series on social media. Show the others a promotional item: bookmarks, a trailer or other things. Create a title and slogan to promote the series. Present the series to your classmates: the main plot, details of the main characters, where it will be set, in which period, etc. As you created the screenplay for the series, you have learnt what atoms are like, why radioactivity exists, the applications of some radioactive isotopes and how radioactive waste should be managed. 3 W E L L D O N E ! Ida Noddack Lise Meitner CHALLENGE 107 ES0000000137418 183391_Unidad04_111062.indd 107 18/7/22 13:51 In addition, there is helpful support material available: A FORMULATION ANNEX at the end of the book will help you to understand and practise chemical nomenclature with activities. A notebook with INNOVATIONS IN SCIENCE helps you to understand the importance of science in our society. THE CHALLENGE 6 2. Binary compounds Annex 1 Binar y compounds resu lt f rom the combinat ion of atoms of t wo chemica l elements. One w i l l have a posit ive ox idat ion number (the electroposit ive element) and the other w i l l have a negat ive ox idat ion number (the electronegat ive element). 2.1. Naming binary compounds Look at how the name of a bina r y compound is formed in t wo d i f ferent ways, using composit iona l nomenclatu re. 2.2. Writing the formula of a binary compound Look at how the formu la of a chemica l compound is formed f rom its name in composit iona l nomenclatu re: Prefixes Dia luminium tr isu lphide AℓS Wr ite the sy mbol of each element in the cor rect order. 1 AℓS Wr ite the sy mbol for each element . The one end ing in –ide w i l l be on the r ight in the formu la . 1 Aℓ2S3 Add the number cor respond ing to the pref i x of each element as a subscr ipt . In th is case, di, 2 for Aℓ and t ri, 3 , for S. 2 Aℓ S Locate the ox idat ion number of the elements in the table: Aℓ, electroposit ive element . Ox idat ion number : +3 S, electronegat ive element . Ox idat ion number : -2 2 Aℓ m Sn m ? (+3) + n ? (-2) = 0 m = 2 n = 3 Aℓ2S3 The sum of the ox idat ion numbers of a l l the elements must be zero for the compound to be neutra l . Find the sma l lest possible subscr ipts to simpl i f y the formu la as much as possible. For example, Aℓ4S6 is a lso va l id , but it shou ld be simpl i f ied . 3 Oxidation numbers A luminium su lphide S O LV E D P R O B L E M 1 Formula Prefixes Oxidation numbers AℓBr3 Aluminium tribromide Aluminium bromide CuCℓ2 Copper dichloride Copper(II) chloride A C T I V I T I E S 1 Name in your notebook: a) PbCℓ2 d) Cr2S3 b) AℓF3 e) Na3N c) BaI2 f ) K2S A C T I V I T I E S 2 Write the formula for: a) Barium chloride b) Tin tetraiodide c) Nitrogen trifluoride d) Mercury dichloride e) Phosphorus pentachloride f ) Iron(III) sulphide g) Cobalt(II) bromide h) Aluminium nitride S O LV E D P R O B L E M 2 Write the formula for these compounds. a) Barium dichloride b) Iron(III) iodide a) On the right, write the symbol of the element ending in -ide: chlorine. Add the subscript, 2, corresponding to the numerical prefix of chlorine, di: BaCℓ2 b) On the right, write the symbol of the element ending in -ide: iodine. To the iodine symbol, add the subscript indicating the oxidation number of iron, which is given by the Roman numeral: FeI3 Look up the ox idat ion number of the electroposit ive element in the table. Wr ite it in Roman numera ls inside brackets a f ter the posit ive element's name, w ithout leav ing a space. I f the element on ly has one ox idat ion number, it is not added to the name. dialuminium trisulphide sulphur tetrachloride aluminium sulphide sulphur(IV) chloride The name of each element is preceded by a pref i x that ind icates the number of atoms of th is element in the formu la : mono, for one. The pref i x mono can be omit ted i f there is no conf usion. di, for t wo. t ri, for three. tet ra, for fou r. penta, for f ive. hexa, for si x , etc. name of the element on the left + name of the element on the right + -ide Using prefixes Using oxidation numbers Look at these examples: Note that S is named after its Latin origin, sulphur. Aℓ only has one oxidation number, so it is not added. element acting as electronegative element acting as electropositive The negative oxidation number of Cℓ is -1. For the compound to be neutral, S must act with its oxidation number +4: +4 + (-1) ? 4 = 0 Element on the right: sulphide Element on the right: chloride Element on the left: aluminium Element on the left: sulphur Aℓ2S3 SCℓ4 The elements combine in a propor t ion that resu lts in a neutra l compound. That is, the sum of the oxidation numbers of all the elements in the formu la must be zero. +3 -2 +3 -2 293 292 ES0000000137418 183391_ANEXOS_115340.indd 292-293 18/7/22 13:36
L E A R N I N G S I T UAT I O N A f itness t est measures your hear t rat e, blood pressure and lung capacity whi le you are exerci sing. Ever ything i s measured in speci f ic units. These measurements are put into a report and analysed . Then a personal training plan is created using this information . Thi s i s an example of applying science to spor t. What would you apply science to that you can see around you? Choose a phenomenon to apply the scienti f ic method to and record a v ideo tutorial to share with your classmat es. Science and measurement 1 Record a video tutorial on the scientific method CHALLE NGE 8
Is a quantity the same as a unit? Classify the terms below as quantities or units. Then group together the units according to the quantity they measure. • Length • Minute • Volume • Second • Kilometre • Time • Metre • Mass • Tonne • Litre • Gram • Cubic metre Can you express the same length in two different units? And the same speed? Give an example. What data can you get from a graph that shows the distance someone travelled over a given time? WORK WITH THE IMAGE We use instruments to measure quantities. The images on the right show a fitness tracker and some mobile phone apps. Look at the graph. What period of time does it show? What quantities are represented on the axes? What units are used? What was the average speed of this person between 6 pm and 7 pm? When did this person take no steps? Is it possible to know the distance this person travelled that day? Make an estimate. L E T ' S G E T S TA R T E D Take act ion "The Sustainable Development Goals (SDGs) are a universal call to action to end poverty, protect the planet and improve the lives and prospects of ever yone, ever ywhere. The 17 Goals were adopted by all UN Member States in 2015, as part of the 2030 Agenda for Sustainable Development." The UN’s 2030 Agenda promotes responsible research and innovation. It is an opportunity for science to work with and for society. Make a start by studying and applying the scientific method in this unit! IN THIS UNIT… Experimental sciences The scientific method Technological applications Measurement Laboratory work Distance walked W N o v Y 1.3 km 2.0 1.5 1.0 0.5 0.0 Oct Oct 29 Oct 18 -19 9
MULTIPLES AND SUBMULTIPLES Mass kg hg dag g dg cg mg : 10 : 10 : 10 : 10 : 10 : 10 #10 #10 #10 #10 #10 #10 Length km hm dam m dm cm mm : 10 : 10 : 10 : 10 : 10 : 10 #10 #10 #10 #10 #10 #10 Area km2 hm2 dam2 m2 dm2 cm2 mm2 : 100 : 100 : 100 : 100 : 100 : 100 #100 #100 #100 #100 #100 #100 Volume km3 hm3 dam3 m3 dm3 cm3 mm3 : 1 000 : 1 000 : 1 000 : 1 000 : 1 000 : 1 000 #1 000 #1 000 #1 000 #1 000 #1 000 #1 000 Capacity kL hL daL L dL cL mL : 10 : 10 : 10 : 10 : 10 : 10 #10 #10 #10 #10 #10 #10 Multiples 101 = 10 102 = 100 103 = 1 000 104 = 10 000 106 = 1 000 000 tens hundreds thousands tens of thousands millions 2 zeros 3 zeros 4 zeros 6 zeros 1 zero Submultiples 10-1 = 1 10 = 0.1 10-2 = 1 102 = 1 100 = 0.01 10-3 = 1 103 = 1 1 000 = 0.001 10-6 = 1 106 = 1 1 000 000 = 0.00 0001 tenths hundredths thousandths millionths 1 zero 2 zeros 3 zeros 6 zeros CONVERTING UNITS MATHEMATICS, PHYSICS AND CHEMISTRY REVISION 1 L = 1 dm3 1 Convert these units: a) 200 g in kg d) 5 dm2 in mm2 b) 33 cL in cm3 e) 3 L in dm3 c) 500 L in m3 f ) 33 cL in L 2 How many milliseconds are in 47 seconds? A C T I V I T I E S #10 #10 #10 #60 #60 #24 : 24 : 60 : 60 : 10 : 10 : 10 d (day) h (hour) min (minute) s (second) ds (decisecond) cs (centisecond) ms (millisecond) CONVERTING UNITS OF TIME S O LV E D P R O B L E M 2 Write 85 cm2 in m2. S O LV E D P R O B L E M 1 Write 0.5 daL in mL. 1. Identify the units. cm2 " m2 2. To go from the first unit to the second, go towards the multiples. The exponent of 10 will be negative. 3. Count the number of steps going from one unit to the other. This is the exponent of 100. m2 dm2 cm2 4. Write the equivalent amount. 85 cm2 = 85 ? 100-2 m2 = 85 ? 10-4 m2 = 0.0085 m2 : 100 2 steps : 100 1. Identify the units. daL " mL 2. To go from the first unit to the second, go towards the submultiples. The exponent of 10 will be positive. 3. Count the number of steps going from one unit to the other. This is the exponent of 10. daL L dL cL mL 4. Write the equivalent amount. 0.5 daL = 0.5 ? 104 mL = 5 000 mL #10 #10 #10 #10 4 steps 10
1 1. Experimental sciences S ci ence i s div i ded into branches that study di f ferent types of probl ems. Here are some examples. Phy sic s a nd chem i st r y a re ex per i ment a l sc iences becau se i n a dd it ion to log ic and obser vation, they a lso use exper imentation and measurement . Science is an act iv it y that solves problems through obser vat ion and log ic. Is astrology a science? Astrolog y and other "occu lt sciences" study phenomena that have no explanation. They are ca l led occu lt because knowledge of them is only avai lable to certain people and remains hidden from others. Unlike real sciences, they are not rational or precise. They are not based on measurement, experiments, data analysis, verif ication or other characteristics of science. They prov ide no reasons or understanding. Astrolog y is not a science! T R U E OR FALSE ? 3 What is science? What are experimental sciences? 4 Decide whether physics or chemistry would study these topics: a) The movement of objects. b) The attraction of magnets. c) The fermentation of wine. d) The melting temperature of metals. 5 Search for information and explain what the sciences in the diagram above study. A C T I V I T I E S Med icine Wh ich vaccine is the best for ma la r ia? Botany Astronomy Optics Biolog y Why do plants g row in some soi ls but not in others? Oncolog y Physics How does water tu rn into steam? Sociolog y Genetics Chemistr y What a re the elements of water? Astrochemistr y Biochemistr y Chemistr y stud ies the chemica l composit ion of mat ter and changes that a f fect its natu re. Chemica l changes transform a substance into another substance. Physics stud ies changes in mat ter that do not a f fect its natu re. A f ter a physica l change, the substance does not change; it is st i l l the same substance. CHALLENGE 11
2. The scientific method Observe a phenomenon Science works by observing a phenomenon and asking questions about it. Why did the bottle of water break when it was in the freezer? What happens to water when it freezes? Search for information Find out whether a solution already exists. • Do you agree with it? • Is there another possible explanation? In general, substances occupy a smaller volume when they are in a solid state than in a liquid state. Water is an exception. Make a hypothesis Think about what you have found out. • What could be a potential answer? • Can you make any predictions? Water increases in size when it freezes. A hypothesis is a possible explanation and it must be tested. Questions help to define the problem we want to study. Discussing the problem with others is very helpful. 6 How is science different from philosophy or religion when explaining what is happening around us? 7 Have you ever needed to use a particular method to complete a task? What was it? Why was it effective? 3 2 1 CHALLENGE 12
1 Publish the results The conclusions of scientific studies are often used to create laws and scientific theories. Glass containers filled with water should not be put in the freezer because they will break. Define the experiment: the quantities you want to measure, the conditions of it and the equipment. The experiments can be done: • In the laboratory. • Outside. This is called fieldwork. Do the data confirm the hypothesis? Experiment Test the hypothesis by doing experiments that simulate the problem. We are going to study the volume that 1 kg of water occupies and its temperature. Analyse the data Use tables to collect the data and graphs to represent and analyse them. It is important to report the results of scientific studies for science to advance. The results are published in articles and books. The scienti f ic method is the set of procedu res and at t itudes we use to study and ex pla in the problems and the phenomena that happen in the un iverse, and come to va l id conclusions. 4 5 6 0 1.0012 1.0010 1.0008 1.0006 1.0004 1.0002 1.0000 4 8 12 16 T (°C) V (dm3) A conference at CERN, the European Organization for Nuclear Research Scientif ic research does not a lways fol low these steps in order or complete them a l l. For example, astronomers can only measure what happens in the universe. They cannot do experiments on it . 13
3. Application of the scientific method 3.1. Observe the phenomenon We ana lyse a phenomenon by using our senses. Through obser vation, we identif y a problem and we ask questions about it . 3.2. Search for information Many quest ions a l ready have an answer. Therefore, we need to f ind relevant informat ion on the subject . 3.3. Make a hypothesis A f ter ident i f y ing the problem and ask ing quest ions, the nex t step is to tr y to f ind answers by ma k ing a hy pothesis. Hy potheses a re g uesses about why rea l events happen. They have to be tested . It is not va l id : it is a quest ion. 8 Observe different objects in free fall. a) What questions would you ask about them? b) Where would you look for information about objects in free fall? 9 Make a hypothesis about the relationship between the mass of an object and how it falls. What experiments would you conduct to test your hypothesis? 10 Apply all the steps in the scientific method to the phenomenon chosen in the challenge. a) What data have you measured in your experiment? b) Why do you think you need to organise the data and make graphs? 11 How would you tell people in your area about the results of your experiment? Obser ve how d i f ferent objects fa l l . Def ine the problem: Not a l l objects fa l l in the same way. Ask quest ions: Why do some objects fa l l faster than others? Why do some objects fa l l in a stra ight l ine but others look l i ke they f loat dow n? Using h is intu it ion, A r istot le sa id that heav ier objects fa l l faster. Many yea rs later, Ga l i leo sa id that a l l objects fa l l at the same speed , i f a i r resistance is ig nored . He d id va r ious ex per iments to prove it . The hy potheses of ou r study a re: " The g reater the mass of an object , the faster it w i l l fa l l when it is d ropped ." " The g reater the mass of an object , the stra ighter its trajector y w i l l be in f ree fa l l ." 1 2 3 Conditions for a valid hypothesis It must be a clear and precise statement. We must be able to test it to prove it is true or false. Aristotle and Galileo: two scientists in action! Does sleeping for f ive hou rs damage the bra in? There are identica l planets to the Earth in other Solar Systems. It is not va l id : it cannot be tested . CHALLENGE 14
1 Prov ing that a hy pothesis is fa lse What i f an ex per iment proves that the hy pothesis is fa lse? Then you have to ma ke a new hy pothesis and test it . For example, ta ke t wo ident ica l sheets of paper. Cr umple one into a ba l l . Watch what happens when you d rop them. The cr umpled paper fa l ls faster. So, we ma ke a new hy pothesis: "The shape of an object a f fects the speed of its fa l l ." 3.4. Experiment We desig n va r ious ex per iments to test whether a hy pothesis is tr ue. Experiment 1: objects in free fall Control the cond it ions: avoid d raughts that cou ld a f fect the fa l l of the objects. 1. Measu re the mass of the objects using sca les. 2 . Place the objects on a h igh hor izonta l su r face. 3. Ti lt the su r face so that they a l l fa l l at the same t ime. 4. Measu re the t ime they ta ke to fa l l . 5. Obser ve the resu lts: Keys Rubber Paper Mass 32 g 7 g 1.5 g Time 0.8 s 1.3 s 5.4 s Conclusion: it seems to be tr ue that heav ier objects fa l l faster. Experiment 2: objects with the same shape in free fall 1. Use an incl ined su r face so the objects ta ke longer to rol l dow n it . 2 . Place objects w ith d i f ferent masses inside ident ica l hol low ba l ls (A , B and C). 3. Li f t the str ip of wood at the sta r t . Measu re the t ime it ta kes the ba l ls to reach each point . 4. Wr ite dow n the resu lts for each ba l l . 4 4 Var iables a re the cha racter ist ics of a phenomenon that can have d i f ferent va lues. In physics and chemistr y, they a re usua l ly quantities such as temperature, mass or pressure. Conduct ing an ex per iment involves repeat ing an obser ved phenomenon under control led cond it ions to f ind out wh ich var iables a f fect it and how. A Steel B Sand C Paper Strip of wood 15
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