Gas Laws

In an ideal gas, if everything else is held constant, doubling the volume will ________ the pressure.

• double

• halve

• not affect

• eliminate

Answer explanation

$PV=nRT$

Since nRT cannot change, neither can PV. If you multiply V by 2, you would have to multiply P by 1/2 to keep the right side constant.

In an ideal gas, if everything else is held constant, tripling the pressure will ________ the Kelvin temperature.

• triple

• cut into a third

• not affect

• equal

Answer explanation

$PV=nRT$

If you multiply P by 3, you would have to multiply T by 3 as well in order to keep the right side equal to the left.

Which of the following is Graham's Law?

• $\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

• $\frac{r_1}{r_2}=\frac{\sqrt{M_2}}{\sqrt{M_1}}$

• $P_1V_1=P_2V_2$

• $PV=nRT$

You stand at the end of a long hallway. At the other end, your classmate releases equal amounts of two gases, carbon-dioxide and chlorine. Which one reaches you first?

• Cl₂

• CO₂

• both arrive at the same time

• need more information

Answer explanation

Lighter gases diffuse faster.

According to kinetic molecular theory: at constant temperature, increasing the volume will decrease the pressure because...

• the gas particles must travel farther from wall to wall.

• P and V are on the same side of the ideal gas law equation.

• the average velocity of the gas particles decreases.

• the potential energy of the gas particles has gone down

Answer explanation

farther travel = fewer collisions per second

In kinetic molecular theory:

pressure = collisions per second between gas and walls of container

temperature = average kinetic energy of gas molecules (as measured by temperature)

According to kinetic molecular theory: at constant volume, increasing the temperature will increase the pressure because...

• the gas particles are moving faster; faster = more collisions-per-second.

• the heat transferred when the temp was raised is stored as potential energy.

• the increased temp makes the gas particles larger resulting in more collisions.

• science.

Answer explanation

increased temp = increased kinetic energy

In kinetic molecular theory:

pressure = collisions per second between gas and walls of container

temperature = average kinetic energy of gas molecules (as measured by temperature

The pressure of a gas at 22 °C goes from 3 atm to 6 atm, with volume held constant. It's new temperature is...

• 44 °C

• 11 °C

• 317 °C

• 0 °C

Answer explanation

The Kelvin temperature doubles.

22 °C = 295 K

295*2 = 590

590 – 273 = 317 °C

According to kinetic molecular theory, more moles of gas means more pressure at the same volume and temperature because...

• more moles = more collisions

• more moles = higher gas constant

• more moles = higher kinetic energy

• more moles = more problems

If no air is added and no air escapes, the tires on a car are flatter in winter than in summer.

• True

• False

Answer explanation

$PV=nRT$

Decrease in T results in a decrease in P if all else is held constant.

What does STP stand for?

(no caps)