Gases

Question 1

What are the characteristic of gases?

Answer 1

They’re a type of fluid that take the shape of their container and is easily compressible.
They’re represented by temperature, pressure, moles, and volume.

Question 2

STP

Answer 2

Standard temperature and pressure.
- 273K or 0C
- 1 atm

• Regardless the identity of a gas if there are equimolar amounts is will occupy the container with the same temperature and pressure.
• At STP 1 mol = 22.3 L

Question 3

Ideal gas law

Answer 3

• Equation that describes the relationship between the 4 variables that describe gas when in an ideal state.
• PV-nRT

Question 4

Avogadro’s Principle

Answer 4

-Direct relationship between volume and moles when temperature and pressure are held constant.

-V1/n1=V2/n2

Question 5

Boyle’s law

Answer 5

Inverse relationship between pressure and volume when temperature and number of moles are held constant.

• P1V1=P2V2

Question 6

Charle’s Law

Answer 6

Direct relationship between volume and temperature when pressure and number of moles are held constant.

• V1/T1= V2/T2

Question 7

Gay- Lussac’s law

Answer 7

There is direct relationship between pressure and temperature.

• P1/T1=P2/V2

Question 8

Relationship between the units of pressure

Answer 8

1 atm = 760 mmHg = 760 torr = 101,325 pa = 101.325 kPa.

** Use these as unit conversions**

Question 9

Dalton’s law of partial pressures

Answer 9

States the the total pressure of a gas system is equal to the sum of the individual partial pressures of the individual gases that make up the system.

• moles of gas/ total moles of gas in system

** When given a fraction convert it to a decimal ( ie. 21% to 0.21)

Question 10

Henry’s Law

Answer 10

States that the solubility of gas is directly proportional to the partial pressure of the gas at the surface of the solution

• C ( concentration of dissolved gas) = k ( henry’s constant) * P ( partial pressure of the gas).

Question 11

Graham’s law

Answer 11

Law that states gas diffusion or effusion happens faster when the molar mass of the gas is less and diffusion or effusion happens slower when the molar mass of the gas is larger.

• Diffusion is the movement of particles from high concentration to low concentration. Effusion is the movement of gas through a narrow opening under pressure.

Question 12

Kinetic Molecular theory

Answer 12

Explains behavior of gasses under certain assumptions:
- gas particles occupy negligible ( zero) volume.
- gas particles doesn’t have intermolecular attractions or repulsions
- gas molecules undergo random collisions with container wall and with other molecules and these collisions are elastic.
- average kinetic energy is directly proportional to temperature.

Question 13

Real gases

Answer 13

Gases that deviate from ideal behavior when under high pressure ( low volume) and low temperature.

• They occupy volume and experience intermolecular attractions or repulsions.

Question 14

van der waals equation of state

Answer 14

used to correct ideal gas law for intermoleculer attraction and occupation of volume for when gases deviate from ideal behavior.