Gas Laws Round 1

Question 1

What is the general gas equation?

Answer 1

PV = nRT, where P = pressure, V = volume, n = moles, R = gas constant, and T = temperature.

Question 2

Define Boyle’s Law.

Answer 2

Boyle’s Law states that at a constant temperature, the pressure of a gas is inversely proportional to its volume (P1V1 = P2V2).

Question 3

Define Charles’s Law.

Answer 3

Charles’s Law states that at constant pressure, the volume of a gas is directly proportional to its temperature (V1/T1 = V2/T2).

Question 4

What is Avogadro’s Law?

Answer 4

Avogadro’s Law states that at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles (V ∝ n).

Question 5

State Gay-Lussac’s Law.

Answer 5

Gay-Lussac’s Law states that at constant volume, the pressure of a gas is directly proportional to its temperature (P1/T1 = P2/T2).

Question 6

What units are commonly used for pressure in gas law calculations?

Answer 6

Atmospheres (atm), millimeters of mercury (mmHg), and Pascals (Pa).

Question 7

What is the standard temperature and pressure (STP) for gases?

Answer 7

0°C (273 K) and 1 atm pressure.

Question 8

What does the ‘R’ in the ideal gas law stand for?

Answer 8

‘R’ is the gas constant, which equals 0.0821 atm·L/(mol·K) when using atm, liters, and Kelvin.

Question 9

What is partial pressure?

Answer 9

The pressure exerted by each individual gas in a mixture.

Question 10

State Dalton’s Law of Partial Pressures.

Answer 10

Dalton’s Law states that the total pressure of a mixture of gases is the sum of the partial pressures of each gas (P_total = P1 + P2 + P3 …).

Question 11

What is diffusion?

Answer 11

The process of gas molecules spreading out to fill the available volume.

Question 12

Define effusion.

Answer 12

Effusion is the process where gas particles escape through a tiny hole into a vacuum.

Question 13

State Graham’s Law of Effusion.

Answer 13

The rate of effusion of a gas is inversely proportional to the square root of its molar mass (Rate1/Rate2 = √(M2/M1)).

Question 14

How does the molar volume of an ideal gas at STP compare across gases?

Answer 14

The molar volume is the same for all ideal gases at STP, approximately 22.4 L.

Question 15

Define the term ‘ideal gas.’

Answer 15

An ideal gas is a hypothetical gas that perfectly follows the gas laws under all conditions.

Question 16

What assumptions are made about ideal gases?

Answer 16

Ideal gases are assumed to have no intermolecular forces and occupy no volume.

Question 17

What is the kinetic molecular theory?

Answer 17

A theory that describes gas behavior in terms of particle motion, collision, and kinetic energy.

Question 18

What is the relationship between kinetic energy and temperature in gases?

Answer 18

The average kinetic energy of gas particles is directly proportional to the absolute temperature.

Question 19

What is meant by ‘real gases’?

Answer 19

Real gases deviate from ideal gas behavior due to intermolecular forces and molecular volume.

Question 20

Under what conditions do gases deviate most from ideal behavior?

Answer 20

At low temperatures and high pressures.

Question 21

What is the Van der Waals equation?

Answer 21

An equation that modifies the ideal gas law to account for intermolecular forces and molecular volume.

Question 22

Why is the ideal gas law considered an approximation?

Answer 22

It assumes gases have no interactions and particles occupy no space, which isn’t true for real gases.

Question 23

What is meant by the compressibility of a gas?

Answer 23

Compressibility measures how much the volume of a gas decreases under pressure.

Question 24

What is molar mass and how is it used in gas law calculations?

Answer 24

Molar mass is the mass of one mole of a substance, used to relate mass to moles in gas calculations.

Question 25

How can you calculate the density of a gas using the ideal gas law?

Answer 25

Density (d) = (PM) / (RT), where M is the molar mass.

Question 26

How does temperature affect gas pressure?

Answer 26

An increase in temperature increases the kinetic energy and thus increases the pressure of a gas.

Question 27

How does molecular weight affect the speed of gas molecules?

Answer 27

Lighter gas molecules move faster than heavier ones at the same temperature.

Question 28

Why do gases have low densities?

Answer 28

The particles are widely spaced, occupying a large volume relative to their mass.

Question 29

Explain why gas pressure is caused.

Answer 29

Pressure is caused by collisions of gas molecules with the walls of their container.

Question 30

What happens to gas volume if the pressure is doubled while temperature remains constant?

Answer 30

The volume is halved (Boyle's Law).

Question 31

How does the addition of gas molecules affect pressure?

Answer 31

Increasing the number of molecules in a fixed volume increases the pressure.

Question 32

What is meant by an elastic collision in the kinetic molecular theory?

Answer 32

A collision where no kinetic energy is lost.

Question 33

What is a vacuum?

Answer 33

A space with no particles and therefore no pressure.

Question 34

Why do gases expand to fill their container?

Answer 34

Gas particles move freely and spread out until they occupy all available space.

Question 35

How does atmospheric pressure change with altitude?

Answer 35

Atmospheric pressure decreases with higher altitude.

Question 36

How does a barometer work?

Answer 36

A barometer measures atmospheric pressure by balancing mercury in a column against air pressure.

Question 37

What is absolute zero?

Answer 37

The theoretical temperature at which all molecular motion stops (0 K or -273.15°C).

Question 38

What happens to gas particles at absolute zero?

Answer 38

They have minimum possible kinetic energy.

Question 39

How does increasing temperature affect gas volume?

Answer 39

Volume increases if the pressure remains constant (Charles's Law).

Question 40

How can molar volume be used to find moles of gas?

Answer 40

At STP, volume (L) divided by 22.4 L/mol gives moles of gas.

Question 41

What is the relationship between the speed of gas molecules and temperature?

Answer 41

As temperature increases, the average speed of gas molecules increases.

Question 42

How does temperature affect the kinetic energy distribution of gas molecules?

Answer 42

Higher temperatures broaden the distribution and increase average kinetic energy.

Question 43

Describe the Maxwell-Boltzmann distribution curve.

Answer 43

It shows the range of speeds of gas molecules at a given temperature.

Question 44

What is the most probable speed in a Maxwell-Boltzmann distribution?

Answer 44

The speed at which the greatest number of molecules move.

Question 45

What is the impact of intermolecular forces on real gas behavior?

Answer 45

Intermolecular attractions reduce the pressure exerted by real gases compared to ideal gases.

Question 46

Explain how a gas exerts pressure on the walls of its container.

Answer 46

Gas particles collide with the container walls, transferring momentum and creating pressure.

Question 47

In terms of kinetic energy, why does a gas expand when heated?

Answer 47

Increased kinetic energy leads to faster-moving particles that spread apart, expanding the volume.

Question 48

How can the ideal gas law be used to calculate molar mass?

Answer 48

Molar mass (M) = (dRT) / P, where d is the density of the gas.

Question 49

How does the real gas equation adjust for the volume of gas particles?

Answer 49

The Van der Waals equation includes a term for particle volume (b).

Question 50

What happens to the ideal gas behavior at very low temperatures?

Answer 50

Ideal gas behavior deviates as particles slow and attractive forces become significant.