Chapter 5

How does Dalton's law of partial pressures help us with our model of ideal gases? That is, what postulates of the kinetic molecular theory does it support?

At the same conditions of pressure and temperature, ammonia gas is less dense than air. Why is this true?

For each of the quantities listed below, explain which of the following properties (mass of the molecule, density of the gas sample, temperature of the gas sample, size of the molecule, and number of moles of gas) must be known to calculate the quantity. a. average kinetic energy b. average number of collisions per second with other gas molecules c. average force of each impact with the wall of the container d. root mean square velocity e. average number of collisions with a given area of the container f. distance between collisions

You have two containers each with 1 mol of xenon gas at ${15}^{\circ }\mathrm{C}$. Container A has a volume of $3.0\mathrm{L}$, and container $\mathrm{B}$ has a volume of $1.0\mathrm{L}$. Explain how the following quantities compare between the two containers. a. the average kinetic energy of the $\mathrm{Xe}$ atoms b. the force with which the Xe atoms collide with the container walls c. the root mean square velocity of the Xe atoms d, the collision frequency of the Xe atoms (with other atoms) e. the pressure of the Xe sample

At room temperature, water is a liquid with a molar volume of $18\mathrm{mL}$. At ${105}^{\circ }\mathrm{C}$ and 1 atm pressure, water is a gas and has a molar volume of over $30\mathrm{L}$. Explain the large difference in molar volumes.

If a barometer were built using water $(d=1.0\mathrm{g}/{\mathrm{cm}}^3)$ instead of mercury $(d=13.6\mathrm{g}/{\mathrm{cm}}^3)$, would the column of water be higher than, lower than, or the same as the column of mercury at $1.00$ atm? If the level is different, by what factor? Explain.

A bag of potato chips is packed and sealed in Los Angeles, California, and then shipped to Lake Tahoe, Nevada, during ski season. It is noticed that the volume of the bag of potato chips has increased upon its arrival in Lake Tahoe. What external conditions would most likely cause the volume increase?

As weather balloons rise from the earth's surface, the pressure of the atmosphere becomes less, tending to cause the volume of the balloons to expand. However, the temperature is much lower in the upper atmosphere than at sea level. Would this temperature effect tend to make such a balloon expand or contract? Weather balloons do, in fact, expand as they rise. What does this tell you?

Which noble gas has the smallest density at STP? Explain.

Consider two different containers, each filled with 2 moles of $\mathrm{Ne}(\mathrm{g}).$ One of the containers is rigid and has constant volume. The other container is flexible (like a balloon) and is capable of changing its volume to keep the external pressure and internal pressure equal to each other. If you raise the temperature in both containers, what happens to the pressure and density of the gas inside each container? Assume a constant external pressure.