Chemistry
Mrs. Westphal
Name:__________________________________
Date:________________
Chemical and Physical Changes Review
Answer the following questions about chemical and physical changes using your notes as necessary.
1. The following are properties of substances. Decide whether each is a physical property (P) or a
chemical property (C).
________A. Helium gas liquefies as -270°C under normal pressure.
________B. Hydrogen burns in sulfur gas.
________C. Mercury is a silver, shiny liquid.
________D.Potassium is a soft, silvery-colored metal.
________E. Iron cars rust in an atmosphere of moist air, especially when coated in road salt.
________F. Zinc metal has a density of 7.13g/mL.
________G.Sodium chloride, table salt, dissolves readily in water.
________H.Sodium bicarbonate, baking soda gives off carbon dioxide when treated with vinegar.
________I. Charcoal burns in oxygen.
________J. Potassium chromate is a yellow, crystalline substance.
2. Identify the physical properties by circling them (the sentence or phrase) and chemical properties by
underlining them.
Iodine is a solid, when stored in a sealed container, having a somewhat lustrous, blue-black
crystal. The crystals vaporize readily to a violet colored gas, which is poisonous. Iodine, like the
other elements in the halogen family, combines with many metals. For example, zinc combines
with iodine to give zinc iodide.
3. Which of the following are physical changes (P) and which are chemical changes (C)?
________A.
Melting of ice cream
________B.
Pulverizing of rock salt to spread on the road.
________C.
Burning of sulfer on the end of matches.
________D.
Melting of silver to make a ring.
________E.
Dissolving of sugar in water to make Kool-Aid.
________F.
Rusting of steel wool sitting in a pool of water.
________G.
Burning of wood in a campfire.
________H.
Evaporation of alcohol from a wound.
4. Identify physical changes by circling them (the sentence or phrase) and chemical changes by
underlining them.
A sample of mercury (II) oxide was heated in a test tube to produce mercury metal and oxygen
gas. Then the liquid mercury was cooled to -40°C, where it solidified. A glowing wood splint
was thrust into the oxygen, and the splint burst into flame.