Chapter 1, Problem 1.24E

What properties distinguish solids from liquids? Liquids from gases? Solids from gases?

The following are properties of substances. Decide whether each is a physical property or a chemical property. a Chlorine gas liquefies at 35C under normal pressure. b Hydrogen burns in chlorine gas. c Bromine melts at 7.2C. d Lithium is a soft, silvery-colored metal. e Iron rusts in an atmosphere of moist air.

Analyses of several samples of a material containing only iron and oxygen gave the following results. Could this material be a compound?

You receive a mixture of table salt and sand and have to separate the mixture into pure substances. Explain how you would carry out this task. Is your method based on physical or chemical properties? Explain.

Suppose someone emptied ball bearings into a container of salt. Could you separate the ball bearings from the salt? How? Would your method involve no change, be a physical change, or be a chemical change?

Aspirin is a pure substance. If you had the choice of buying a widely advertised brand of aspirin whose effectiveness is well known or the generic product of a new manufacturer at half the price, which would you buy? Explain.

Decide whether each of the following is a physical property or a chemical property of the substance. a Salt substitute, potassium chloride, dissolves in water. b Seashells, calcium carbonate, fizz when immersed in vinegar. c The gas hydrogen sulfide smells like rotten eggs. d Fine steel wool (Fe) can be burned in air. e Pure water freezes at 0C.

The following photo shows the element potassium reacting with water to from the element hydrogen, a gas, and a solution of the compound potassium hydroxide. (a) What states of matter are involved in the reaction? (b) Is the observed change chemical or physical? (c) What are the reactants in this reaction, and what are the produces? (d) What qualitative observations can be made concerning this reaction?

In the following description of the element bromine, identify which of the properties are chemical and which are physical. Bromine is one of the few elements that is a liquid at room temperature. It is an acrid-smelling substance that reacts readily with most metals. It evaporates easily, so most containers of bromine are filled with visible amounts of red fumes. Most bromine is obtained from sodium bromide, a compound found in salt beds.