It indicates the mass per unit of volume. d m V = The three cylinders have the same mass. Iron and brass have similar densities; aluminium is less dense because it occupies more volume. Density It is the amount of a substance that can be dissolved in 100 g of water. Solubility in water It measures resistance to scratching on a scale of 1 to 10. Talc is the softest material; it can be scratched with a fingernail . Its hardness is 1. Diamond is the hardest; it can scratch any other material . Its hardness is 10. Hardness Metals are good conductors of electricity and heat, while wood and plastic are bad conductors. Electrical and thermal conductivity It is the temperature at which a solid turns into a liquid. At a pressure of 1 atmosphere, ice melts at 0 °C. Melting point It is the temperature at which a liquid boils. At a pressure of 1 atmosphere, water boils at 100 °C. Boiling point 1 Characteristic or specific properties of matter 9 In your notebook, match each of these objects with the property for which it is most commonly used. Copper wire Melting point Steel saucepan Electrical conductivity Cork stopper Solubility in milk Cocoa powder Density Antifreeze liquid Thermal conductivity 10 Graduated cylinder A contains water and B contains alcohol. Which of these properties will allow you to identify the two substances? a) Mass d ) Volume b) Colour e ) Boiling point c) Smell f ) Density A C T I V I T I E S A B 200 g of sugar can be dissolved in 100 g of water. Oil does not dissolve in water. Brass Iron Aluminium Talc Diamond 13
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