Gas Laws

Question 1

What happened in the marshmallow lab when we pushed the syringe in with a marshmallow?

Answer 1

Gas is compact which squished the marshmallow. Less volume = more pressure. More pressure = more collisions hitting the marshmallow explaining why it shrunk.

Question 2

What happened in the marshmallow lab when we pulled the syringe with a marshmallow?

Answer 2

Gas particles pulled apart expanding the marshmallow. More volume = less pressure. Less pressure means less collisions.

Question 3

Kinetic Theory

Answer 3

All matter consists of tiny particles in constant motion.

Question 4

3 Assumptions of Kinetic Theory

Answer 4

1.) Particles in gas = small hard spheres w/ insignificant volume (lot of space between w/ no attraction or repulsion)
2.) Motion of particles = rapid, constant, and random (gases fill container no matter the volume)
3.) All collisions between gas = perfectly elastic

Question 5

Random Walk

Answer 5

aimless path molecules travel

Question 6

Gas Pressure

Answer 6

The result of billions of rapidly moving particles in gas simultaneously colliding w/ an object.

Question 7

Vacuum

Answer 7

empty space w/ no particles and no pressure.

Question 8

How is Atmospheric Pressure formed?

Answer 8

Gravity holds gases in air down and they collide w/ objects on Earth’s surface.

Question 9

Barometer

Answer 9

Device used to measure atmospheric pressure

Question 10

SI unit of Pressure

Answer 10

Pascal (Pa)

Question 11

Standard Units of Pressure

Answer 11

101.3kpa = 1atm = 760mmHg = 14.7psi

Question 12

Absolute Zero

Answer 12

The temp. at which motion of particles theoretically ceases (zero degrees Kelvin)

Question 13

1 mol of gas is how many liters

Answer 13

22.4 L

Question 14

Factors Affecting Gas Pressure

Answer 14

1.) Volume (L)
2.) Temp, (K)
3.) # mols of gas (n)

Question 15

Ideal Gas Law

Answer 15

helps calculate how much of a gas there is at different conditions

Question 16

If you have more of a gas it can occupy _______ space (volume)

Answer 16

more

Question 17

Real Gases do have ________ and are affected by attractive forces between molecules.

Answer 17

volume

Question 18

Partial Pressure depends on what 2 things?

Answer 18

1.) # of particles in a given volume
2.) average KE

Question 19

What happens to a gas when released?

Answer 19

moves from high to low concentration (diffusion)

Question 20

Effusion

Answer 20

when gas diffuses through tiny hole in a container

Question 21

If the mass of a molecule is larger, it travels ________.

Answer 21

slower

Question 22

Volume vs. Pressure

Answer 22

Inversely proportional (BOYLES LAW). Temperature is held constant.

Question 23

Volume vs. Temperature

Answer 23

Directly proportional (CHARLES LAW). Pressure is held constant.

Question 24

Pressure vs. Temperature

Answer 24

Directly proportional (AMONTON’S LAW/GAY- LUSSAC’S). Volume is held constant.

Question 25

Dalton’s Law of Partial Pressure

Answer 25

In a mixture of gasses the contribution of each gas in a mixture to the total pressure. Sum off all the partial pressures of the gas.
Diffusion: When a gas is released it tends to move from higher concentration to lower concentration.
Effusion: If the gas diffuses through a tiny hole in a container.
PTotal = P1+P2+P3+P4

Question 26

Relationship between the energy, speed, and mass of a gas. (Graham’s Law)

Answer 26

When gasses are at the same temperature they have the same kinetic energy.
Larger the mass of the molecule the slower it travels.
The rates of effusion of two gasses are inversely proportional to the square roots of their molar masses. Graham’s law is a ratio comparing how fast gas A is compared to gas B. If the answer is <1 gas A is slower. If the answer is >1 Gas A is faster.
Lighter gases move faster. But two gasses at the same temperature have the same kinetic energy.