11 Gases and Kinetic Molecular Theory Online Quiz Questions

A fixed amount of gas begins at $1.20\ \mathrm{atm}$, $2.50\ \mathrm L$, and $300\ \mathrm K$. It changes to $0.800\ \mathrm{atm}$ and $360\ \mathrm K$. Find its final volume and explain how the pressure and temperature changes affect the result.

A gas at $0.80\ \mathrm{atm}$ and $6.0\ \mathrm L$ is compressed to $2.0\ \mathrm L$, then allowed to expand to $3.0\ \mathrm L$. The temperature and amount of gas remain constant throughout. What is the final pressure, and why is it valid to compare the initial and final states directly?

A fixed amount of gas occupies $2.00\ \mathrm L$ at $250\ \mathrm K$ in a flexible container held at constant pressure. It is warmed to $300\ \mathrm K$, then cooled to $280\ \mathrm K$. Find the volume at each later temperature and explain how the final volume compares with both the intermediate and initial volumes.

A rigid tank contains a fixed amount of gas at $1.00\ \mathrm{atm}$ and $300\ \mathrm K$. The gas is heated to $450\ \mathrm K$. Determine the new pressure and explain why heating changes pressure rather than the tank’s volume.

A flexible container holds $0.40\ \mathrm{mol}$ of gas in $5.0\ \mathrm L$. At constant pressure and temperature, an additional $0.16\ \mathrm{mol}$ is added. Find the new volume and explain how the change in amount determines it.

A gas occupies $2.50\ \mathrm L$ at $98.0\ \mathrm{kPa}$ and $310\ \mathrm K$. Use the ideal gas equation to find the amount of gas in moles. State which value of $R$ you use and explain how its units match the data.

A nonreacting ideal-gas mixture contains $0.50\ \mathrm{mol}$ of $\mathrm{N_2}$, $1.50\ \mathrm{mol}$ of $\mathrm{O_2}$, and $2.00\ \mathrm{mol}$ of $\mathrm{Ar}$ at a total pressure of $4.00\ \mathrm{atm}$. Find each component’s mole fraction and partial pressure, then check that the partial pressures are consistent with Dalton’s law.

A nonreacting ideal-gas mixture has a total pressure of $2.00\ \mathrm{atm}$. Components $A$ and $B$ have partial pressures of $0.60\ \mathrm{atm}$ and $0.90\ \mathrm{atm}$, respectively. If the mixture contains $4.0\ \mathrm{mol}$ in total, determine component $C$’s partial pressure, mole fraction, and amount.

Two gases are at the same temperature. Their particles have molar masses of $4\ \mathrm{g\,mol^{-1}}$ and $16\ \mathrm{g\,mol^{-1}}$. Which gas has the greater average particle speed, by what factor, and how does the average translational kinetic energy per particle compare?

Equal amounts of the same gas start at the same temperature in two containers. One container is rigid; the other has a freely moving piston that keeps pressure constant. Both samples are heated to the same higher temperature. Using kinetic molecular theory, compare their average translational kinetic energies and explain why one container’s pressure rises while the other expands.

A gas can be studied in either a warm, low-pressure state or a cool, highly compressed state. In which state should the ideal-gas equation be the better approximation? Explain how particle volume and intermolecular attractions help account for the difference.

A fixed amount of gas at constant temperature occupies $3.00\ \mathrm{L}$ at $1.20\ \mathrm{atm}$. It is compressed to $1.80\ \mathrm{L}$. Which gas-law relationship applies, and what is its final pressure? Show your calculation and include units.

A flexible container holds a fixed amount of gas at constant pressure. Its volume is $2.40\ \mathrm{L}$ at $300.0\ \mathrm{K}$. If the gas is heated to $400.0\ \mathrm{K}$, what volume does it occupy? Identify the relationship you use, show the calculation, and include units.

A rigid container holds a fixed amount of gas at $95.0\ \mathrm{kPa}$ and $20.0\ ^\circ\mathrm{C}$. The gas is heated to $80.0\ ^\circ\mathrm{C}$. Assuming the volume does not change, identify the applicable relationship and calculate the final pressure in kilopascals. Show the kelvin conversions and calculation.

A flexible container holds $0.80\ \mathrm{mol}$ of gas in a volume of $2.00\ \mathrm{L}$. More gas is added until the container holds $1.20\ \mathrm{mol}$, while pressure and temperature remain constant. What is the new volume? Name the relationship used and show your calculation.

A fixed amount of gas changes from $P_1=0.950\ \mathrm{atm}$, $V_1=2.50\ \mathrm{L}$, and $T_1=300\ \mathrm{K}$ to $P_2=1.20\ \mathrm{atm}$ and $T_2=360\ \mathrm{K}$. Determine its final volume. Show the equation, rearrangement, and calculation.

An ideal gas has a pressure of $98.0\ \mathrm{kPa}$, a volume of $4.50\ \mathrm{L}$, and a temperature of $300\ \mathrm{K}$. Calculate the amount of gas in moles using $R=8.314\ \mathrm{L\,kPa\,mol^{-1}\,K^{-1}}$. Show how you rearrange the ideal gas equation and report your answer to three significant figures.

A nonreacting ideal-gas mixture contains $0.35\ \mathrm{mol}$ of gas $A$ and $0.65\ \mathrm{mol}$ of gas $B$. The total pressure is $2.40\ \mathrm{atm}$. Calculate each component’s partial pressure and verify that your results are consistent with Dalton’s law. Show your work.

A nonreacting ideal-gas mixture has a total pressure of $2.50\ \mathrm{atm}$. Component $A$ contributes $0.750\ \mathrm{atm}$, and the mixture contains $2.00\ \mathrm{mol}$ total gas. Determine the mole fraction and amount of $A$, then find the amount of all other gases combined. Explain the relationships you use.

Two different ideal gases are at the same temperature. Compare their particles’ average translational kinetic energies and their average speeds if one gas’s particles are lighter. Explain why these comparisons are not contradictory.

Use kinetic molecular theory to explain why heating a gas raises its pressure in a rigid container, but causes expansion when pressure is held constant. Your explanation must distinguish what happens to particle motion and to collisions with the container walls in each case.

A student must decide whether the ideal-gas model is more likely to be accurate for a gas at relatively low pressure and high temperature or at relatively high pressure and low temperature. Choose the more favorable conditions for the model and explain how the assumptions about particle volume and intermolecular forces support your choice.

A rigid container holds $0.400\ \mathrm{mol}$ of ideal gas at $95.0\ \mathrm{kPa}$. The temperature is maintained constant while an additional $0.200\ \mathrm{mol}$ of the same gas is added. Assuming the final state is ideal, calculate the final pressure. Explain why pressure changes in proportion to the amount under these conditions.

A fixed amount of gas at constant temperature occupies 3.60 L at 0.850 atm. It is compressed until its pressure is 2.00 atm. Determine its final volume and explain which gas-law relationship you used.

A flexible container holds 2.40 L of gas at 25.0 °C. At constant pressure, it is heated to 125.0 °C. Determine its final volume and show why the temperatures must be converted before using the gas-law relationship.

An ideal gas sample contains 0.750 mol at 2.50 atm and 315 K. Determine its volume in liters. State which value of $R$ you use and explain why its units are appropriate.

A nonreacting ideal-gas mixture contains 2.00 mol of gas A and 1.00 mol of gas B at a total pressure of 3.60 atm. Calculate each gas’s partial pressure and verify that the results are consistent with Dalton’s law.

Two different gases are at the same temperature, but one gas’s particles are lighter. A student claims the two gases must have the same average particle speed. Evaluate the claim using kinetic molecular theory, stating what quantity is the same and what differs.

A gas sample is cooled substantially while being compressed to high pressure. Explain why the ideal-gas approximation may become less reliable under these conditions. Identify the kinetic molecular theory assumptions that are challenged, and do not assume that the deviations must have a particular direction.

A student argues that because gas-particle collisions are elastic, each particle must leave every collision with exactly the same kinetic energy it had before. Is that conclusion justified? Explain what elastic collisions conserve and how the particles' individual kinetic energies may change.