Physics and Chemistry S E C O N D A R Y 4 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 Annabel Maybank María del Carmen Vidal Rosalie Wheeler EDITORS Bárbara Braña 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 ion 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 Matter: gases and solutions 8 Write a scientific report, applying the scientific method SDG 4: Quality education Target 4.4 2 Atoms and the periodic table 34 Design a periodic table with applications of the chemical elements SDG 12: Responsible consumption and production Target 12.8 3 Bonds and chemical compounds 58 Develop a website about new materials SDG 9: Industry, innovation and infrastructure Target 9.5 4 Carbon chemistry 80 Design an organic compounds game SDG 3: Good health and well-being Target 3.4 5 Chemical reactions 106 Make a podcast about a chemical process and its effects on the environment SDG 8: Decent work and economic growth Target 8.4 6 Motion 136 Promote a campaign to enforce compliance with speed limits SDG 3: Good health and well-being Target 3.6
Essent i a l knowl edge Sc i ent i f i c work Cr i t i ca l think ing 1. Gases 2. Gas laws. The Boyle-Mariotte law 3. Gas laws. Gay-Lussac's law 4. Gas laws. Charles' law 5. The general ideal gas equation 6. The ideal gas equation of state 7. The kinetic theory of gases 8. Solutions - Relate atmospheric pressure and the Boyle-Mariotte law - Relate hot-air balloon flights to Charles' law - Simulate the behaviour of gases - Publish a scientific study - Differentiate between concentration by mass and density - Prepare a solution Can spray paints explode? 1. Particles that make up atoms 2. Atomic models 3. The distribution of electrons in atoms 4. The periodic table of elements 5. Periodic properties of elements - Create a periodic table - Analyse the properties of the metallic elements Aℓ, Mg and Na 1. Chemical bonds 2. Ionic bonds 3. Covalent bonds 4. Metallic bonds 5. Bonds between molecules 6. Properties of substances and types of bonds - Analyse how soap cleans - Relate the properties of substances to the type of bond Does soap destroy coronavirus? 1. Carbon compounds 2. Hydrocarbons 3. Oxygen compounds 4. Nitrogen compounds 5. Oxygen and nitrogen compounds around us 6. Organic compounds of biological interest - Make aspirin Does drinking lots of water dissolve excess cholesterol? 1. Chemical reactions 2. Energy in chemical reactions 3. The speed of chemical reactions 4. Chemical reaction calculations 5. Acid and base reactions 6. Combustion reactions 7. Electrochemical reactions - Study the law of conservation of matter - Prepare an acid-base indicator - Detect CO2 in respiration 1. Quantities describing motion 2. Velocity 3. Uniform rectilinear motion (URM) 4. Acceleration 5. Uniformly accelerated rectilinear motion (UARM) 6. Uniform circular motion (UCM) - Understand the characteristics of a URM from the position-time graph - Measure the instantaneous velocity in a UARM - Analyse the route of a circuit Is it just as safe to go 50 km/h as 30 km/h in a city?
Contents Uni t Learning s i tuat ion 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 162 Develop an experiment on friction and analyse industry-related innovations SDG 9: Industry, innovation and infrastructure Target 9.5 8 Gravitational forces 186 Write a research report on a mystery of the Universe SDG 9: Industry, innovation and infrastructure Target 9.5 9 Forces in fluids 206 Explain how some of the machines around us work. SDG 9: Industry, innovation and infrastructure Target 9.b 10 Energy and its transfer 230 Design a campaign to promote energy saving SDG 7: Affordable and clean energy Target 7.1 11 Waves. Light and sound 262 Improve the lighting and acoustics of a room SDG 7: Affordable and clean energy Target 7.3 Annexes 294
Essent i a l knowl edge Sc i ent i f i c work Cr i t i ca l think ing 1. Forces and changes in speed 2. The action of various forces 3. Forces acting on bodies. Weight, normal force, friction, buoyancy and tension 4. Newton's laws of dynamics 5. Forces and motion - Check that the resultant force has the same effect as the initial forces - Relate the force applied to a body to its acceleration - Experiment with the fundamental principle of dynamics Can a car move without using fuel? 1. Gravitational force 2. The weight and acceleration of gravity 3. The motion of planets and satellites - Analyse the Cavendish experiment to find the value of G - Use virtual animations to study the motion of a satellite - Analyse astronomical images Is space exploration a waste of money with no practical applications? 1. Pressure 2. Hydrostatic pressure 3. Atmospheric pressure 4. Transmission of pressure in fluids 5. Buoyancy force on submerged bodies 6. Physics in the atmosphere - Experimentally test the forces exerted in a liquid - Measure the density of a liquid using communicating vessels - Experimentally test for the presence of atmospheric pressure -Analyse how pressure is transmitted in a fluid -Analyse the forces involved in an experiment -Apply Archimedes' principle Does 1 kg of iron weigh more than 1 kg of cork? 1. What is work? 2. Work and mechanical energy 3. Mechanical power and efficiency 4. What is heat? 5. Energy in our daily lives - Study the conservation of mechanical energy - Measure the specific heat of a substance Are there machines that work without consuming energy? 1. Wave motion 2. Sound 3. Light 4. Properties of light and sound 5. Applications of light and sound - Measure the speed of sound in air - Test the reflection of light in flat mirrors - Test the refraction of light Do headphones damage hearing? Formulas of inorganic compounds Formulas of organic 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 L E A R N I N G S I T UAT I O N In recent years, molecular gastronomy has brought ver y innovative utensils and techniques into the kitchen . Chefs almost appear to be working in a physics and chemistr y laborator y. And this is what molecular gastronomy consists of: applying scientific knowledge to understand and explore culinar y possibilities. A knowledge of gases and mixtures of substances is essential to many spectacular dishes. And comprehensive knowledge goes hand in hand with the scientific method . Take act ion As you write the report and apply the scientific method , you will learn the steps that rigorous work requires, from planning it to publishing the results. This will help you to become a valuable professional , and you will be able to contribute to sustainable development. Target 4.4: "By 2030, substantially increase the number of youths and adults who have relevant skills, including technical and vocational skills, for employment, decent jobs and entrepreneurship." Matter: gases and solutions 1 Most of the matter around us is in a solid, liquid or gaseous state. Which of the following characteristics correspond to each state? • It has a fixed shape. • It has a fixed volume. • It can be compressed. • It expands. • It needs to be in a container to handle it (say whether the container is open or closed). What is a homogeneous mixture? What about a heterogeneous mixture? Give examples, indicating which substances make up the mixture in each case. WORK WITH THE IMAGE Imagine that this glass has been left on a table to observe how it evolves over time. In what physical state is the glass? What about the red matter? And the white matter? Why is the white matter coming out of the glass? Will all the white matter come out of the glass? Will we stop seeing it as white matter? Explain what is happening to it. Will room temperature influence the process? L E T ' S G E T S TA R T E D IN THIS UNIT. . . Gases The gas laws. The BoyleMariotte law. Gay-Lussac's law. Charles' law The general ideal gas equation The ideal gas equation of state The kinetic theory of gases Solutions Write a scientific report, applying the scientific method CHALLE NGE 9 8 WHAT MAKES UP MATTER? ATOMS PHYSICS AND CHEMISTRY REVISION Made up of several substances Several distinguishable components Same type of atoms The components are indistinguishable Made up of a single substance Different types of atoms Homogeneous or solutions Heterogeneous Simple substances Atoms are the building blocks of all matter. Currently, 118 dif ferent types of atoms are known . These atoms make up each of the 118 chemical elements. Compounds MATTER The symbol of the element it belongs to is the first letter of the Latin name of the element. The mass number, A, is the number of protons plus the number of neutrons. The atomic number, Z, indicates the number of protons. If the atom is neutral , it coincides with the number of electrons. O A Z X 16 8 + Proton : particle with a positive electric charge Neutron : particle with no electric charge - Electron : particle with a negative electric charge Shell Nucleus Mixtures Pure substances 1 Use the periodic table in the annex to complete the following table in your notebook. (P: no. of protons; E: no. of electrons; N: no. of neutrons.) Name Symbol Z A P E N A Bromine 80 35Br 35 80 35 35 45 B ... ... 18 40 ... ... ... C ... 190 76Os ... ... ... ... ... D Barium ... ... 137 ... ... ... E ... ... ... ... 63 ... 89 F ... 23 11Na ... ... ... ... ... G Thorium ... ... ... ... ... 142 H ... ... 207 82 ... ... A C T I V I T I E S 36 1 Relate hot-air balloon flights to Charles' law The history of hot-air balloons is closely related to Jacques Charles. His studies made it possible to calculate the volume increase that a gas experiences when it is heated to a certain temperature, keeping it at atmospheric pressure. How is the flight of a hot-air balloon controlled? • Some hot-air balloons are made of a flexible material. In some balloons a gas that is lighter than air is used. This was hydrogen at first, but today it is helium. • When heated, the temperature of the gas increases and it expands. As the hot-air balloon and its gas are in the atmosphere, the process is performed at a constant pressure (atmospheric pressure). Volume and temperature are directly proportional (Charles' law). • The balloon, with the hot gas, is less dense than air, and can ascend and keep itself in flight. • To descend, the gas is no longer heated. The temperature decreases and, with it, the volume in the same proportion. • The density of the air in the balloon gradually increases and the balloon can descend. SOLVED PROBLEM 4 In a kitchen, where the temperature is 30 °C, there is a bottle partially filled with water. The free space of 200 mL is occupied by a gas. We put it in the fridge, where the temperature is 4 °C. What volume does the gas in the bottle occupy? If the bottle is made of soft plastic, what happens to it? 1. Write the two states of the gas with their quantities. p1 = 1 atm V1 = 200 mL T1 = 30 °C p2 = 1 atm V2 = ? T2 = 4 °C 2. Identify the law to apply. For a transformation when p = constant, apply Charles’ law. V T V T 1 1 2 2 = 3. Make V2 the subject. V T V T V T V T V T T V 1 1 2 2 1 2 2 1 2 2 1 1 = → ⋅ = ⋅ → = ⋅ 4. Before substituting the data, write all the amounts of each quantity in the same units. The temperature must be in kelvin: T1 (K) = T1 (°C) + 273 = 30 °C + 273 = 303 K T2 (K) = T2 (°C) + 273 = 4 °C + 273 = 277 K Apply Charles’ law: V T T V 2 2 1 1 182 8 = = = ⋅ ⋅ 277 K 303 K 200 mL . mL The gas occupies a smaller volume. If the bottle is soft plastic, it will get crushed. 12 A balloon occupies a volume of 1 m3 at a temperature of 20 °C. The gas inside is heated to 100 °C. What will be its volume now if the process took place at atmospheric pressure? 13 Explain whether this is true: “When a gas experiences transformations at a constant pressure, its volume and temperature are directly proportional. That is, if its temperature goes from 20 °C to 40 °C, its volume also doubles.” A C T I V I T I E S 17 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. 4. Gas laws. Charles' law Simulate the behaviour of gases Steps This application allows you to simulate the behaviour of gases. You can reproduce experiments to see the effect of temperature on particle velocity, deduce laws, etc. It is found at phet.colorado.edu. 14 Simulate the conditions in which a gas experiences transformations at V = constant, p = constant and T = constant. In each case, complete a table of data for the independent variable and the dependent variable. Draw a graph of the data and deduce the corresponding law. Conclusions 1. Choose the study of Laws. 2. Select the quantity that will remain constant. 3. Select whether you want to display the Width of the container (to give an idea of the volume), the Stopwatch and the Collision Counter (to give an idea of the pressure). 4. Move the piston up and down one or more times to allow particles to enter the gas chamber. 5. Move the slider up or down to make the temperature hotter or colder. The temperature of the container will change accordingly (you can display it in °C or in K). 6. Read the resulting pressure (you can choose to display it in kPa or atm). Options for studying transformations at a constant pressure. You can change the volume of the container by var ying the width . 2 5 5 6 4 1 3 18 1 Can spray paints explode? Spray cans contain gas at a high pressure (between 2 and 8 atm) that helps to get the contents out. These cans are metal containers, so the gas is at a constant volume. If they are placed near a heat source, the gas heats up and its pressure increases (Gay-Lussac’s law). The pressure can be so high that the walls of the can cannot support it and it explodes. If a can of spray paint is thrown into a fire, it can explode! SOLVED PROBLEM 3 When a 500 mL can of spray paint is empty, the gas inside exerts a pressure of 1 atm at room temperature, which is 20 °C. If it is placed near fire, it can reach 800 °C. What pressure will the gas exert at that time? 1. Write down the two states of the gas with their quantities. p1 = 1 atm V1 = 500 mL T1 = 20 °C p2 = ? V2 = 500 mL T2 = 800 ºC 2. Identify the law to apply. For a transformation when V = constant, apply Gay-Lussac’s law. p T p T 1 1 2 2 = 3. Make p2 the subject. p T p T p T p T p T T p 1 1 2 2 1 2 2 1 2 2 1 1 = → ⋅ = ⋅ → = ⋅ 4. Before substituting the data, write all the amounts of each quantity in the same units. The temperature must be in kelvin: T1 (K) = T1 (°C) + 273 = 20 °C + 273 = 293 K T2 (K) = T2 (°C) + 273 = 800 °C + 273 = 1073 K Apply Gay-Lussac’s law: p T T p 2 2 1 1 = = = ⋅ ⋅ 1073 K 293 K 1 atm 3.7 atm 8 A 700 cm3 rigid container was filled with nitrogen gas. The manometer indicated a pressure of 100 kPa at 25 °C. What temperature will the gas be if the manometer indicates a pressure of 5 atm? 10 The manometer on a 100 L cylinder indicates that the gas inside it exerts a pressure of 1 atm at room temperature (20 °C). What pressure will it exert when its temperature reaches 130 ºC? 9 Pressure cookers cook food faster and with less water. At the high pressure inside, water boils at over 100 °C. Look at the diagram and answer: a) What type of matter is in the space above the fill limit line? What state is it in? b) Why does it have an airtight lid? c) Explain the function of the vent pipe and the safety valve. What could happen if it didn’t have them? d) It is necessary to check that the valves are not blocked, due to the risk of explosion. Use Gay-Lussac’s law to explain why it could explode. A C T I V I T I E S Vent pipe (releases steam when the pressure reaches the limit) Safety valve Airtight lid Fill limit line T R U E OR FALSE ? 15 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. The electronic configuration of an atom is the way in which its electrons are distributed around the nucleus. It follows three principles. The electronic configuration of an atom can be represented in various ways. Look at the example of a sulphur atom (Z = 16). The electronic configuration of an atom can also be written by taking the nearest previous noble gas and adding the atom's valence electrons. Valence electrons are the electrons of the outermost layer of an atom. 3. The distribution of electrons in atoms 16 Choose a chemical element whose atomic number means something to you, such as your age or your shoe size. Make a poster showing its symbol and electronic distribution. The auf bau's principle of minimum energy Electrons occupy the lowest energy orbital available. The energy order of the orbitals does not coincide exactly with the order of the levels and sub-levels. Moeller's diagram is used to establish the correct order. This is a simple mnemonic tool that helps us remember the order, and it does not follow the laws of physics. The diagram only shows the dif ferent types of orbitals. Square 2p represents the three p orbitals; square 3d represents the five d orbitals; and square 4f represents the seven f orbitals. Pauli 's exclusion principle In 1922, the spin of electrons was discovered . It was proved that this quantity can only have two values, represented by vertical arrows, one pointing up and the other pointing down . According to the exclusion principle, no two electrons in the same atom can be in the same state. Therefore, no more than two electrons can occupy the same orbital and they must have opposite spins. Hund 's rule of maximum multiplicity The most stable electronic configuration is the one with the most electrons with the same spin (called unpaired electrons). If there are three electrons in three p orbitals with the same amount of energy, each electron will occupy a p orbital . All three electrons will have the same spin. 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 7p 3d 4d 5d 6d 7d 4f 5f 6f 7f An electron's spin is represented by an arrow pointing up or down . Maximum number of electrons in each sub-level . Sub-level No. of electrons s 1 orbital ® 2 p 3 orbitals ® 6 d 5 orbitals ® 10 f 7 orbitals ® 14 1s 2s 2p 3s 3p S (Z = 16): 1s2 2s22p6 3s23p23p13p1 n = 3 n = 2 n = 1 1s 2p 3p 2s 3s Start: lowest energy Each arrow represents an electron. CHALLENGE Element Z Electronic configuration Ne 10 1s2 2s22p6 S 16 1s2 2s22p6 3s23p4 = [Ne] 3s23p4 46 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. Boyle–Mariotte law when the … is constant, the product of the … the gas exerts and the volume it occupies remains constant the ideal gas equation of … KINETIC THEORY OF GASES GAS LAWS GAS EQUATIONS the general ideal gas equation p1 · V1 T1 = p2 · V2 T2 components concentration solute: it is in the … proportion … : it is in the highest proportion gases are made up of small … moving in a straight line the gas occupies the whole volume of the … there are no bonding … between the particles in a gas the pressure exerted is a measure of the number of … the temperature is proportional to the … of the particles Charles' law … when the … is constant, the quotient of the pressure the gas exerts and its absolute … remains constant when the … is constant, the quotient of the … of the gas and its absolute temperature remains constant p · … = n · R · T relates the p, V and … of a gas in two states relates the p, … and T of a gas and the moles (n) percentage by mass: % msolute = mass of solute mass of solution · 100 percentage by … : % Vsolute = volume of solute volume of solution · 100 concentration by … : Csolute = mass of solute volume of solution · 100 molarity: … = nsolute Lsolution SOLUTIONS 7 1 26 TA B L E . Copy and complete the table in your notebook. Atom Z A Protons Electrons Neutrons C 6 … … … 6 O … 16 8 … … F 9 19 … … … 27 D R AW I N G . In your notebook, match each atomic model to its name: Rutherford's model Quantum mechanical model Bohr's model Thomson's model 28 S U M M A R Y. In your notebook, match each sentence to the atomic model it relates to: Rutherford's model Quantum-mechanical model Bohr's model Thomson's model A. The atom is a positively charged mass with electrons scattered throughout it. B. Electrons are distributed in energy layers or levels. C. The gold foil experiment showed this model was wrong. D. This model explains why atoms produce line spectra. E. It describes an atom with a very small nucleus and lots of empty space between the electrons and the nucleus. F. This model explains all the lines in atomic spectra. G. It does not explain why the electrons do not end up falling into the nucleus. 29 TA B L E . In your notebook, draw two tables similar to the one below. Complete the information about the different particles in SI units and on the atomic scale. Proton Electron Neutron Mass … … … Charge … … … 30 V O C A B U L A R Y. Define these terms: a) Orbital b) Electronic configuration c) Ion d) Metallic character 31 S U M M A R Y. For each of the orbitals s, p, d and f, complete the sentences below in your notebook: a) In layer 2, there are … and … type orbitals. b) In each layer, there is one orbital of type … . 32 D R AW I N G . In your notebook, match each drawing to the type of orbital it represents. s p d f 33 S U M M A R Y. In your notebook, complete each sentence and indicate which principle it relates to: a) An atom cannot contain two … in the same state. b) Electrons occupy the … energy orbital available. c) The most stable electronic configuration is the one with the most electrons with the same … . The aufbau's principle Pauli's principle Hund's rule o r g a n i s e yo u r i d e a s Particles of an atom S O LV E D P R O B L E M 3 Calculate the mass of a proton and the mass of an electron in atomic units. Write down the relationship between the units. For the proton: mp = 1 67 10 1 66 10 27 27 . . ⋅ ⋅ ⋅ − − kg 1u kg » 1 u For the electron: me = 9.11 kg 1u 1.66 kg ⋅ ⋅ ⋅ = − − 10 10 31 27 5.49 10 u 4 ⋅ − 34 Indicate the number of protons, neutrons and electrons in each of these atoms: a) 16 8O c) 14 7N e) 4 2He g) 238 92U b) 14 6C d) 12 6C f ) 37 17Cℓ h) 197 79Au Atomic models 35 Review the gold foil experiment and explain whether these conclusions can be reached: a) Atoms are indivisible particles. b) Electrons are arranged in layers. c) Most of an atom is empty. 36 These sentences refer to Bohr's atomic model. Explain which one is correct: a) Protons orbit the nucleus without emitting energy. b) Electrons orbit the nucleus in specific orbits. c) Neutrons orbit the nucleus at any distance. 37 These sentences refer to the quantum-mechanical model. Explain if they are correct: a) Each electron spins around the nucleus in an orbit. b) In the first level, there are no p orbitals. c) In the second level, there are five d orbitals. d) 2p orbitals have less energy than 3p orbitals. 38 Indicate in your notebook whether there are differences in size and shape between these pairs of orbitals. a) 2s and 3p b) 2s and 5s c) 3d and 4d d) 2p and 3d 39 Do drawings to compare each of these pairs of orbitals: a) 1s and 2s b) 1s and 4s c) 2p and 3p d) 2s and 2p 40 Observe the electronic configuration of a phosphorus atom below and answer: 1s 2p 2s 3s 3p a) What does the electronic configuration of an atom represent? Write the electronic configuration of phosphorus using only letters and numbers. b) What three principles determine the electronic configuration of an atom? S O LV E D P R O B L E M 4 Write down the electronic configuration of cobalt. Find the atomic number of cobalt, Co, in the periodic table. Z = 27, each atom has 27 electrons. Use Möller's diagram and place 2 electrons in each orbital until you reach the total: 1s2 2s2 2p6 3s2 3p6 4s2 3d7 Remember to follow the three principles. Energy level Configuration Interpretation 1 1s2 It has 2 electrons in the 1s orbital. 2 2s2 2p6 It has 2 electrons in the 2s orbital. It has 2 electrons in each of the three 2p orbitals. 3 3s2 3p6 It has 2 electrons in the 3s orbital. It has 2 electrons in each of the 3p orbitals. 3 and 4 4s2 3d7 It has 2 electrons in the 4s orbital. The 4s orbital fills up before the 3d orbital. It has 7 electrons in the five 3d orbitals. According to Hund's rule of maximum multiplicity, first one electron occupies each d orbital and then they gradually fill up. c h e c k yo u r p r o g r e s s 2 a) c) b) d) a) c) b) d) e) f ) Use the STUDY NOTES to review the content of this unit. 55 54 Carbon nanotubes There are many applications that can obtain significant benefits from incorporating carbon nanotubes. For example, in fuel cells, nanotube-reinforced composites, field emitters in f lat screens, biological and chemical sensors to detect pollutants, and the release of drugs and medicines into the body. In general , sectors such as electronics, materials, sensors, biotechnology, chemistr y, energy, mechanics, scientific instrumentation and photonics could gain an advantage by introducing carbon nanotubes into many of their products. [...] In both cases, their main characteristic, which is responsible for many of their exceptional properties, is that they have a very high length-to-diameter ratio. Their diameter is in nanometres and their length can vary from a few micrometres to millimetres, and even a few centimetres. meetthings.com (Adapted) Single-walled carbon nanotubes (SWCNT) are composed of carbon atoms arranged in a hexagonal network and forming a cylinder. Their structure is the same as the structure that would be obtained by rolling up a sheet of graphite. They can be closed at the ends by half spheres of fullerene, or they can be open . Multi-walled carbon nanotubes (MWCNT) have a structure similar to a concentric arrangement of several SWCNTs with dif ferent diameters. > What type of bond joins carbon atoms together in nanotubes? Explain your answer. > Do you think nanotubes of iron could be made? Why? Carbon nanotubes are similar to small graphite sheets rolled into cylinders, with diameters measured in nanometres and lengths in micrometres. 14 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. 55 The label on a bottle of perfume indicates that it is 80 % alcohol by volume. Calculate the amount of alcohol needed to prepare the 280 mL of perfume in the bottle. 56 Some "non-alcoholic" beers can contain up to 1 % alcohol. In a half-litre bottle of this type of beer, how much alcohol will there be? 57 C H E M I S T R Y A N D C O O K I N G Spherification is a commonly seen molecular cooking technique. It was popularised by chef Ferrán Adrià, although it has been known since 1946. It consists of enclosing a liquid inside a semi-solid membrane. To achieve this, a substance called sodium alginate must be added to the food. Drops of this mixture are then added to a bath of calcium chloride dissolved in water. After a few seconds, balls that resemble caviar can be collected. One of the keys to success is to be precise with the concentrations. You have to add 10 g of calcium chloride per litre of water. a) What is the molar concentration of the calcium chloride solution? b) How much calcium chloride do you need to prepare 100 cm3 of solution? S O LV E D P R O B L E M 1 3 Sodium sulphide (Na2S) is a water-soluble substance used as a bleach in the textile industry. a) How much Na2S do you need to prepare 500 mL of 1.5 M solution? b) What is the concentration of the sodium ion (Na+) in that solution? a) Calculate the amount of solute you need to prepare that amount of solution. M n V L s = → ( ) substitute the data: ns = M × V (L) = 1.5 M × 0.5 L = 0.75 mol To know the equivalent mass to these moles of solute, you must calculate their molar mass (M). M (Na2S) = 23 × 2 + 32.06 = 78.06 g/mol 0 75 1 . mol mol 78.06 g of Na S of Na S of Na S 2 2 2 ⋅ =58.55 g of Na S 2 b) When dissolved in water, Na2S separates into ions: Na2S ® 2 Na + + S2– Each mol of Na2S gives 2 mol of Na +. Therefore: The concentration of Na+ in the solution is: 2 × 1.5 M = 3 M 58 We prepare a solution by dissolving 15 mL of 1.5 M Na2S in water until it reaches 100 mL. What is the concentration of the new solution? 59 The solubility of some substances in water varies greatly with temperature. The graph shows the maximum amount of potassium nitrate (KNO3) that can be dissolved in 100 g of water at different temperatures. Solubility (g of solute/100 g of water) 20 30 50 60 70 80 90 40 100 200 180 160 140 120 100 80 60 40 20 0 T (°C) a) Read on the graph the solubility of KNO3 in water at 75 ºC. Express it as a percentage by mass. b) Determine whether we can prepare a solution of 30 % KNO3 in water at 45 ºC. c h e c k yo u r p r o g r e s s 32 41 Write the electronic configuration of the elements Ce, Xe, W and Pb in your notebook and interpret it. 42 Read the news article and answer in your notebook. A mother from San Diego wins the Nobel Prize This was the headline in a local newspaper announcing her award in 1963. Sixty years after Marie Curie won the Nobel Prize in Physics, the German physicist Maria Goeppert Mayer won the prize for her model that explained the nucleus of atoms: inside the nucleus, protons and neutrons are arranged in layers, according to their energy level . Her expertise in mathematics led her to make this discovery, which had an important impact on nuclear physics. Goeppert shone in a field that was traditionally dominated by men. Her recognition came after a long scientific career "on loan", in which she spent many years working without pay. bbvaopenmind .com (Adapted) a) Review the history of the atom. Find the names of the people who devised models to explain it. b) What other subjects played a role in Goeppert's discovery? Why was her model influential? c) Think about the headline in the local newspaper. Do you think it is appropriate? Why? Write a more appropriate headline for this news article. S O LV E D P R O B L E M 5 Write the electronic configuration of these atoms and ions. What do they have in common? Atom/ Ion No. of protons No. of electrons Electronic configuration 20 10Ne 10 10 1s 2 2s2 2p6 19 9F-1 9 10 1s2 2s2 2p6 24 12Mg2+ 12 10 1s2 2s2 2p6 They all have the same number of electrons. Chemical species (atoms or ions) that have the same electron configuration are called isoelectronic. 43 In your notebook, complete a similar table to the one in the previous example with the electronic configuration of Rb1+, Cℓ1-, Ca2+ and Se2-. Which noble gas has the same configuration as each of them? The periodic table of elements 44 Make a table in your notebook with the columns below. Complete the information for the elements Ne, F, O, I, Be, B and Cu. Element Z Electronic configuration Group Period Metal/ nonmetal Ne ... ... ... ... ... 45 The electronic configurations of different elements are: A: 1s2 2s1 C: 1s2 2s22p6 B: 1s2 2s22p5 D: 1s2 2s22p6 3s1 Correct the errors in these statements in your notebook: a) A is a nonmetal from group 1 and period 2. b) A and D belong to the same period. c) B and C are nonmetals. d) D is a metal from group 3 and period 1. Periodic properties of elements 46 Order the atoms from the smallest to the largest size: a) Cs, Li, Na c) P, N, As b) C, Li, Ne d) Mg, Ar, Na c h e c k yo u r p r o g r e s s 47 C H E M I S T R Y A N D M E D I C I N E . Chemical elements have diverse applications. Some are used as contrast agents to diagnose diseases in imaging techniques. For example, gadolinium is used in MRI (magnetic resonance imaging ) and the f luorine-18 isotope is used in PET (positron emission tomography). The element binds to proteins in tumour cells and causes a bright signal to be emitted that makes it easier to identify the tumour. Others are known poisons, such as mercur y and thallium. They are mentioned in classic works of literature. The Mad Hatter in Lewis Carroll 's Alice in Wonderland was poisoned by mercur y vapour. In The Pale Horse, Agatha Christie describes thallium as the perfect poison , as it is dif ficult to identify. dciencia .es (Adapted) 56 S O LV E D P R O B L E M 1 4 A 20 % glucose infusion is a solution of sugar in water with a density of 1.15 g/cm3. We want to prepare half a litre of 20 % glucose infusion. Calculate the amount of sugar needed. Solution: 20 % glucose infusion d = 1.15 g/cm3 V = 1500 mL Solute: sugar Solvent: water Using the density of the solution, calculate the mass equivalent to 500 mL: d m v m d V = → = ⋅ = ⋅ = 1.15 g 500 575 g mL mL Use the richness of sugar in the glucose infusion as a conversion factor: 575 20 10 g of infusion g of sugar g of infusion ⋅ = 115 g of sugar 60 To prepare half a litre of a solution of sodium chloride (NaCℓ) in water at 5 % by mass, how much sodium chloride will you need? Data: dsolution = 1.05 g/cm3. 61 We prepare a solution by mixing 20 g of sodium hydroxide in 200 mL of water. The density of the solution is 113 g/mL. Calculate the concentration in percentage by mass, in g/L, and molarity (M). 1 62 Analyse the news article. What exactly i s homeopathy? Homeopathy is based on a doctrine developed by the German physician Samuel Hahnemann at the end of the 18th centur y. It is based on the principle that " like cures like". According to it, the same substance that causes symptoms of a disease must be used to cure it, diluted in water in infinitesimal proportions. For example, caf feine wakes us up, but if taken in tiny proportions it does the opposite: it makes us sleepy. A homeopathic preparation for sleeping can be obtained by mixing one part of caf feine with 99 parts of water. It is shaken and the solution is mixed with another 99 parts of water. And so on . These preparations are usually taken in the form of sucrose and water tablets. Sometimes, no traces of the active ingredient to be administered remain in the tablet. The scientific evidence against the ef fectiveness of homeopathy is irrefutable. 13 years ago, the prestigious medical journal The Lancet ended the debate in an editorial entitled The end of homeopathy. elpais.com (Adapted) a) Imagine that you dissolve 1 g of glucose (C6H12O6) in water until it reaches 100 mL. What is its molarity? How many moles of glucose does 1 mL of this solution contain? b) Now add water to that 1 mL of solution until you have a final volume of 100 mL. What is the molarity of the glucose solution now? c) Use the results of the above calculations to prove that homeopathy is pseudoscience. Write a scientific report, applying the scientific method It is time to write the report for one of your scientific studies. Present it in the form of written text or as the script of an audiovisual production. You can start with a scientific problem from this unit or look for another one. Follow the scientific method, from observing to communicating the results. Remember that science has an important social responsibility. In addition to publishing in a journal, you should write an article to inform the general public. It is a good idea to include drawings or diagrams that help people to understand what you have studied and its consequences. While you were creating your report, you learnt the stages of the scientific method and applied them to the study of gases and solutions. W E L L D O N E ! CHALLENGE 33 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 In recent years, molecular gastronomy has brought ver y innovative utensils and techniques into the kitchen . Chefs almost appear to be working in a physics and chemistr y laborator y. And this is what molecular gastronomy consists of: applying scientific knowledge to understand and explore culinar y possibilities. A knowledge of gases and mixtures of substances is essential to many spectacular dishes. And comprehensive knowledge goes hand in hand with the scientific method . Matter: gases and solutions 1 Write a scientific report, applying the scientific method CHALLE NGE 8
Take act ion As you write the report and apply the scientific method , you will learn the steps that rigorous work requires, from planning it to publishing the results. This will help you to become a valuable professional , and you will be able to contribute to sustainable development. Target 4.4: "By 2030, substantially increase the number of youths and adults who have relevant skills, including technical and vocational skills, for employment, decent jobs and entrepreneurship." Most of the matter around us is in a solid, liquid or gaseous state. Which of the following characteristics correspond to each state? • It has a fixed shape. • It has a fixed volume. • It can be compressed. • It expands. • It needs to be in a container to handle it (say whether the container is open or closed). What is a homogeneous mixture? What about a heterogeneous mixture? Give examples, indicating which substances make up the mixture in each case. WORK WITH THE IMAGE Imagine that this glass has been left on a table to observe how it evolves over time. In what physical state is the glass? What about the red matter? And the white matter? Why is the white matter coming out of the glass? Will all the white matter come out of the glass? Will we stop seeing it as white matter? Explain what is happening to it. Will room temperature influence the process? L E T ' S G E T S TA R T E D IN THIS UNIT. . . Gases The gas laws. The BoyleMariotte law. Gay-Lussac's law. Charles' law The general ideal gas equation The ideal gas equation of state The kinetic theory of gases Solutions 9
THE SCIENTIFIC METHOD PHYSICS AND CHEMISTRY REVISION 1 We observe that when a glass bottle filled with water is left in the freezer, it breaks. Which of these are valid hypotheses? Why? a) Low temperature causes glass to break. b) The volume of water increases when it freezes. c) The force exerted by the water breaks the glass. 2 Convert these units: a) 5 L ® cm3 d) 100 dm3 ® m3 b) 5 atm ® hPa e) 1 000 mmHg ® atm c) 0.05 m3 ® L f ) 70 kPa ® atm A C T I V I T I E S QUANTITIES, UNITS AND CONVERTING UNITS A quantity is a property of matter that can be measured . It can be written as a number and a unit. We use a conversion factor to change one unit into another unit. Units of pressure hPa (hectopascal) ×100 : 100 Pa (pascal) : 101300 × 101300 atm (atmosphere) × 760 : 760 mmHg Units of volume m3 × 1000 : 1000 dm3 L × 1000 : 1000 cm3 mL A hypothesis is a possible explanation and it must be tested. Define the experiment: the quantities you want to measure, the conditions of it and the equipment. Analyse the data Use tables to collect the data and graphs to represent and analyse them. 4 3 5 2 6 1 Observe a phenomenon Science works by observing a phenomenon and asking questions about it. Publish the results The conclusions of scientific studies are often used to create laws and scientific theories. Experiment The hypothesis is tested by doing experiments that simulate the problem. Search for information Find out whether a solution already exists. Do you agree with it? Is there another possible explanation? Make a hypothesis Think about what you have found out and think of a reasonable answer or prediction. The results are published in articles and books. The scientific method is the set of processes and attitudes that we use to study and explain the phenomena that happen in the universe, and come to valid conclusions. A hypothesis is a provisional statement used in scientific research. It may or may not be true. S O LV E D P R O B L E M 1 Write 120 hPa in mmHg. Use a conversion factor for each change of unit: 120 760 900 hPa 100 Pa 1 hPa 1 atm 101 300 Pa mmHg 1 atm mmHg ⋅ ⋅ ⋅ = Conversion factor Conversion factor Conversion factor 10
1 1. Gases 1.1. The states of matter Review the states of matter and their characteristics. 1.2. The study of gases The volume of a gas depends on temperature and pressure. The scientific method can be used to find the relationship between these quantities. We cannot use a single experiment to measure the relationship between the three variables. We have to design experiments in which one of them remains constant ( for example, temperature), we vary the second variable ( for example, volume) and measure its ef fect on the third (pressure). The independent variable is the quantity we var y. The dependent variable is the quantity in which we measure the ef fect. In addition , we have to use a device that allows us to read the value of the three quantities and var y the independent variable in each case. In all the experiments we must measure these quantities: volume (V ), pressure (p) and temperature (T ). During the 17th centur y, several scientists carried out experiments in England and France. They were able to establish the gas laws. 3 Make three drawings that explain the characteristics of matter in each of the states. Draw little balls to represent the particles that form matter as in the image. Solids They have a fixed shape and volume. They cannot expand or be compressed . Liquids They have a variable shape, but a fixed volume. They do not expand , and can be compressed a little. Gases They have a variable shape and volume. They can expand and be compressed . Device used to study gases. 30 L 20 L 10 L 0 L Thermometer Movable piston (it goes up or down to change the volume) Manometer Temperature must always be expressed in K (SI unit). If it is measured in °C, we must convert the unit: T (K) = T (°C) + 273 Volume and pressure can be expressed in any unit. We must use the same unit throughout the experiment. CHALLENGE Liquid Liquid 11
2. Gas laws. The Boyle-Mariotte law In the 17th centur y, Robert Boyle in England and Edme Mariotte in France studied the variations in the pressure of a gas when the volume of the container changed and the temperature remained constant. We can perform similar experiments, applying the scientific method . Experiment ⇒ Use a thermostatic bath and set the temperature to TA. • Move the piston to set the volume to V1. • On the manometer, read the value of the pressure, p1. • Write down the values of V1 and p1 in a row in a table. • Repeat until there are several rows of data. ⇒ Change the temperature of the thermostatic bath to TB. • Repeat the steps to obtain another series of data. TA p1 TA p2 1 Data collection 15 12 9 6 3 15 30 p (atm) V (L) 0 0 TA < TB A Experiment A (constant TA) Experiment B (constant TB) V (L) p (atm) V (L) p (atm) 30 0.5 30 1 15 1.0 15 2 10 1.5 10 3 7.5 2.0 7.5 4 6.0 2.5 6.0 5 5.0 3.0 5.0 6 3.0 5.0 3.0 10 2 Table Graph dependent variable dependent variable independent variable independent variable Data analysis ⇒ The greater the volume, the lower the pressure, and vice versa. ⇒ In each row, the product of p × V remains constant. Its value depends on the temperature. ⇒ The pressure-volume graph is a hyperbola. ⇒ The curvature of the hyperbola depends on the temperature. 3 Conclusion ⇒ Pressure and volume are inversely proportional quantities. 4 4 Why does a plastic bottle get crushed during a plane landing? p × V = constant p1 × V1 = p2 × V2 The Boyle-Mariotte law When a gas experiences transformations at a constant temperature, the product of the pressure it exerts and the volume it occupies remains constant. CHALLENGE V1 V2 B 12
1 Relate atmospheric pressure and the Boyle-Mariotte law Observe what happens to a bottle of water during a plane landing. Why does the bottle get crushed? • Inside the plane, the temperature remains constant. • There is gas above the water in the bottle. Some of it is water that has evaporated, and some of it is air that entered when we opened the bottle to drink. • During the descent, the atmospheric pressure inside the plane increases. This causes the volume occupied by the gas to decrease and the bottle is crushed. This is what the Boyle-Mariotte law predicts. SOLVED PROBLEM 2 A plane is flying at an altitude of 10 000 m and at 20 °C. Inside, there is a bottle partially filled with water. In the free space inside the bottle, 200 mL is occupied by a gas at a pressure of 750 hPa. On landing, without the temperature changing, the pressure reaches 1 atm. What volume does the gas in the bottle occupy? 1. Write down the two states of the gas with their quantities. p1 = 750 hPa V1 = 200 mL T1 = 20 °C p2 = 1 atm V2 = ? T2 = 20 °C 2. Identify the law to apply. For a transformation when T = constant, apply the Boyle-Mariotte law: p v p v 1 1 2 2 ⋅ = ⋅ . 3. Make V2 the subject. p V p V V p p V 1 1 2 2 2 1 2 1 ⋅ ⋅ → ⋅ = = 4. Before substituting the data, write all the amounts of each quantity in the same units. 1 atm 103.25 hPa 1 atm 1013 hPa ⋅ = v p p v 2 1 2 1 = ⋅ = = 750 hPa 1013 hPa 200 mL 148 mL The bottle when the plane is flying at 10 000 m. The bottle when the plane has landed. 5 WO R K W I T H T H E I M AG E . Push the piston of a syringe up to the first mark (A). Then cover the hole with one finger and push the piston with your thumb (B). You will notice that the piston goes quite far into the cylinder. Now, while still covering the hole, remove your thumb and let the piston move. You will see that it returns to its starting position. a) What is inside the syringe all the time? b) Does the amount of matter inside the syringe change during the experiment? c) What happens to the volume of that matter when you push the piston? Why? 6 A 6 L container is filled with nitrogen gas at a pressure of 5 atm. a) What volume will it occupy if we double the pressure without changing the temperature? b) What pressure should be exerted for the volume to reach 15 L? A C T I V I T I E S A B 13
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