physical science exam 2 review

The percentage composition by mass of water is approximately a. 2% H and 1% O. b. 11% H and 89% O. c. 1% H and 99% O. d. 2% H and 16% O.

11% H and 89% O.

. A compound consists of only magnesium, carbon, and oxygen. If the percentage by mass of Mg is 28.8% and that of C is 14.2%, what is the percentage by mass of O? a. 16.0% b. 57.0% c. 43.0% d. 22.5% e. None of the above

57.0%

The ratio by mass of carbon to hydrogen in 100 g of a certain compound is 6 to 1. The ratio in 200 g of the same compound will be a. 24 to 1. b. 6 to 1. c. 12 to 1. d. none of these.

6 to 1

What is the formula mass of ammonium phosphide, (NH4)3P? a. 85.0 u b. 49.0 u c. 48.0 u d. 57.0 u

85.0 u

The formula mass of sulfuric acid, H2SO4, is a. 98 u. b. 100 u. c. 66 u. d. 7 u.

98 u

An element that tends to gain electrons during chemical reactions is probably a. a semimetal. b. a nonmetal. c. an actinide. d. a metal.

a nonmetal

The law of definite proportions states that different samples of a pure compound always contain the same elements in the same proportion by a. mass. b. atoms. c. atomic number. d. volume.

mass