Problem 12
Why is \(\mathrm{N}_{2}\) a gas at room temperature? Explain why lowering the temperature allows for liquid \(\mathrm{N}_{2}\) to form.
Problem 14
The nonpolar hydrocarbon \(\mathrm{C}_{25} \mathrm{H}_{52}\) is a solid at room temperature. Its boiling point is greater than \(400^{\circ} \mathrm{C} .\) Which has the stronger intermolecular forces, \(\mathrm{C}_{25} \mathrm{H}_{52}\) or \(\mathrm{H}_{2} \mathrm{O}\) ? Explain.
Problem 16
Hydrogen bonding is a special case of very strong dipole–dipole interactions possible among only certain atoms. What atoms in addition to hydrogen are necessary for hydrogen bonding? How does the small size of the hydrogen atom contribute to the unusual strength of the dipole–dipole forces involved in hydrogen bonding?
Problem 17
Which gas, \(\mathrm{CO}\) or \(\mathrm{N}_{2},\) is expected to behave more ideally at 10 \(\mathrm{atm}\) and \(-50^{\circ} \mathrm{C} ?\)
Problem 18
The conductivity of silicon is enhanced by doping. What is doping?
Problem 19
Atoms are assumed to touch in closest packed structures, yet every closest packed unit cell contains a significant amount of empty space. Why?
Problem 20
Define critical temperature and critical pressure. In terms of the kinetic molecular theory, why is it impossible for a substance to exist as a liquid above its critical temperature?
Problem 21
What is an alloy? Explain the differences in structure between substitutional and interstitial alloys. Give an example of each type.
Problem 22
Describe what is meant by a dynamic equilibrium in terms of the vapor pressure of a liquid.
Problem 23
How does each of the following affect the rate of evaporation of a liquid in an open dish? a. intermolecular forces b. temperature c. surface area
