Choose the best description of temperature.

(a) a relative measure of hotness and coldness

(b) a measure of the average molecular kinetic energy of a substance

(c) both (a) and (b)

Glycerol (propane-1,2,3-triol) is a viscous syrup with molecular weight 92 g/mol, boiling point $290^{\circ} \mathrm{C}$, and density 1.24 g/mL. Transforming the three hydroxyl groups into their trimethylsilyl ethers (using chlorotrimethylsilane and a tertiary amine) produces a liquid that flows easily, has molecular weight 309 g/mol, boiling point approximately $180^{\circ} \mathrm{C}$, and density 0.88 g/mL. Draw the structures of these two compounds and explain why glycerol has a lower molecular weight but a much higher boiling point and density.

Draw the condensed structural formulas and write the $IUPAC$ names for two structural isomers of the carboxylic acids that have the molecular formula $C_4H_8O_2$

What type of solid (network, metallic, Group 8A, ionic, or molecular) will each of the following substances form? $\mathrm{NH}_{3}$

Circle the letter of the instrument shown that is used to measure mass.
a. scale
b. balance beam
c. platform balance
d. analytical balance

How could you determine quantitatively whether the ionic compound table salt or the molecular compound table sugar is more soluble in water?

As far as we know, molecular clouds are the only places other than planets that contain the kinds of complex molecules needed to support life, including water molecules and many more complex organic molecules. Do you think it is possible for life to exist in a molecular cloud? What would life have to be like to survive there?

A classmate tells you that experimental data shows a compound’s molecular formula to be 2.5 times its empirical formula. Is he correct? Explain.

Which group of morphologically unusual bacteria, absent from molecular surveys of prokaryotes in the rumen, seem to dominate activities in the termite hindgut?

What is the total mass of all the oxygen molecules in a cubic meter of air at normal temperature $\left(25^{\circ} \mathrm{C}\right)$ and pressure (1.01-10. $\mathrm{Pa}$ )? Note that air is about $21 \%$ (by volume) oxygen (molecular $\mathrm{O}_2$ ), with the remainder being primarily nitrogen (molecular $\mathrm{N}_2$ ).

Use analytical methods to evaluate the following limits.

$$\lim _ { x \rightarrow 1 } \frac { x \ln x + \ln x - 2 x + 2 } { x ^ { 2 } \ln ^ { 3 } x }$$

What two molecular mechanisms can explain the phenomenon of gene conversion? Would both occur in the double-strand break model?

An unknown gas $X$ effuses $1.65$ times faster than $\mathrm{C}_3 \mathrm{H}_8$. What is the molecular mass of gas $X$ ?

Which of these compounds are molecular: $\mathrm{CBr}_4$, $\mathrm{FeS}$, $\mathrm{P}_4 \mathrm{O}_6$, $\mathrm{PbF}_2$?