CHEM Describing the Characteristics of Matter We describe Chemistry as the science concerned with the properties, composition, and behaviour of matter. We describe the Physical and Chemical Properties of matter and the Physical and Chemical Changes that Matter can go through when it is heated, cooled, combined or separated. Chemistry is the Science of TRANSFORMATION! We should recall the properties of Solids, Liquids and Gases and be able to describe their different properties and the simple molecular motions and arrangements of the particles. Physical and Chemical Properties If any of the following words are new to you, be sure you look up the meaning of the word. You should be able to explain what each of these properties are and provide an example. of matter are usually those that we can observe with our senses. A substance's physical property allows us to identify the substance without causing a change in the composition of the substance. Physical Properties Some examples of Physical Properties are: • • • • • • • • • • • • physical state (solid, liquid or gas at certain temperatures and pressures) colour odor solubility in water density melting point boiling point hardness ductility hardness malleability conductivity of matter are those that relate to how the substance changes in composition or how it interacts with other substances. Chemical Properties Some examples of Chemical Properties are: • • • • • • • • • • • Heat of combustion Reactivity with water pH oxidizing ability paper burns iron rusts gold does not rust wood rots nitrogen does not burn silver does not react with water sodium reacts with water In each of these, the substance's chemical property is its tendency to: i. react ii. tarnish iii. corrode iv. explode 1. Determine whether each of the following properties is physical or chemical. o (a) A block of styrofoam floats on water. o (b) Sugar becomes caramel when heated above its melting point. o (c) Iron dissolves in hydrochloric acid and hydrogen gas evolves. o (d) Lithium metal has a shiny surface. After exposure to air, it becomes dull. o (e) An iron nail is attracted to a magnet. Physical and Chemical Changes Some examples of Physical Changes are: • • • • • • cutting a piece of paper ice melting boiling water drawing copper into a fine wire separating out water from seawater separating out oxygen gas from air Some examples of Chemical Changes are: • • • • iron turning into rust in moist air extracting sulfur from car battery acid overtime, a battery loses its charge digesting food 2. Determine whether each of the following is either a chemical change or a physical change. o (a) pure water from seawater o (b)Electricity is passed through water to produce hydrogen and oxygen gases. o (c) A white T-shirt is dyed red. o (d) A wet mop dries in the sun. o (e) Making ice cube in the freezer.