Physics 2110 -- Problem Set #1
1. The density of solid lithium is 534 kg/m3. Look up the atomic mass number of
naturally occurring lithium in a periodic table (such as the end page of your text).
Calculate the average atomic spacing in solid lithium to three significant figures.
2. The density of solid copper is 8900 kg/m3. Look up the atomic mass number of
naturally occurring copper. Calculate the average atomic spacing in solid copper to three
significant figures.
3. The density of solid gold is 19,300 kg/m3. Look up the atomic mass number of
naturally occurring gold. Calculate the average atomic spacing in solid gold to three
significant figures.
4. The density of liquid mercury is 13,600 kg/m3. Look up the atomic mass number of
naturally occurring mercury. Calculate the average atomic spacing in liquid mercury to
three significant figures.
5. The density of liquid ethyl alcohol is 806 kg/m3. An ethyl alcohol molecule contains 2
carbons, 6 hydrogens, and 1 oxygen. What is the average mass number per atom of ethyl
alcohol? Calculate the average atomic spacing in liquid ethyl alcohol to three significant
figures.
6. The five previous problems represent atomic spacings in a broad range of solids and
liquids. If you were asked to make a broad generalization about the atomic spacing in
solids and liquids from these results what would you say?
7. Solids and liquids are very difficult to compress. The atoms are packed in them about
as tightly as is possible. Atomic spacings for solids and liquids, therefore, are
approximately the diameters of the respective atoms. Gases, on the other hand, can be
compressed quite easily. The density of helium at room temperature and atmospheric
pressure is 0.179 kg/m3. Calculate the atomic spacing in gaseous helium. This result is
typical of many gases. If you were asked to make a generalization from these data,
comparing atomic spacings in solids and liquids versus gases, what would you say?