Chapter 1, Problem 1.14E

All of the following processes involve a separation of either a mixture into substances or a compound into elements. For each, decide whether a physical process or a chemical reaction is required. a Sodium metal is obtained from the substance sodium chloride. b Iron filings are separated from sand by using a magnet. c Sugar crystals are separated from a sugar syrup by evaporation of water. d Fine crystals of silver chloride are separated from a suspension of the crystals in water. e Copper is produced when zinc metal is placed in a solution of copper(II) sulfate, a compound.

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.

Which of the following are the same and which are different? a. a substance and a pure substance b. a heterogeneous mixture and a solution c. a substance and a mixture d. a homogeneous mixture and a solution

Some ice cubes are homogeneous and some are heterogeneous. Into which group do ice cubes from your home refrigerator fall? If homogeneous ice cubes are floating on water in a glass, are the contents of the glass homogeneous or heterogeneous? Justify both answers.

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.

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

Which of the following are pure substances and which are mixtures? For each, list all of the different phases present. a bromine liquid and its vapor b paint, containing a liquid solution and a dispersed solid pigment c partially molten iron d baking powder containing sodium hydrogen carbonate and potassium hydrogen tartrate

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.