Gas Conversions and Gas Laws

Water Density

• 13.6

• divide by this anytime have water (wet stoichiometry)

How many mmHg are in 1 atm?

760 mmHg

How many torr are in 1 atm?

760 torr

How many kPa are in 1 atm?

101.3 kPa

How many psi are in 1 atm?

14.7 psi

Boyle's Law (relationship between Pressure and Volume)

P₁V₁ = P₂V₂

Gay-Lussac Law (relationship between Pressure and Temperature)

P₁/T₁ = P₂/T₂ *Temperature must be in Kelvin (°C + 273)

Charles Law (relationship between Volume and Temperature)

V₁/T₁ = V₂/T₂ *Temperature must be in Kelvin (°C + 273)

Combined Gas Law

(P₁V₁)/T₁ = (P₂V₂)/T₂ *Temperature must be in Kelvin (°C + 273)

What is STP (standard temperature and pressure)?

• standard temperature: 0°C

• standard pressure: 1 atm

Avagadro's Law

V₁/n₁ = V₂/n₂ *n must be in moles

Ideal Gas Law

PV = nRT *P must be in atm, V must be in liters (L), n must be in moles, R is 0.0821, T must be in Kelvin

Gas Density

D = M/V *M must be in grams, V must be in liters (L)

Gas Molar Mass

mass/mole

Dry Stoichiometry

1. set up chemical reaction equation (balance it)

2. calculate the stoichiometry (mole, given and actual)

3. input the moles for the substance need to find as n in the ideal gas law equation (PV=nRT) to find the volume of substance

Wet Stoichiometry

1. Find the pressure of gas needed, use the equation: *P = Patm(mmHg) +/- (level difference)/13.6 - PH20 (found from water temperature, on chart)*

2. add (+) (level difference)/13.6 if gas is stronger (water below the water line)

3. subtract (-) (level difference)/13.6 if gas is weaker (above the water line)

4. set up chemical reaction equation (balance it)

5. do dry stoichiometry (pay attention to units, pressure may not be in atm)

Mole Fraction

• moles of individual gas / moles of total gas

• 2 parts should add up to 1

Speed of Gas (m/s)

• √3RT/molar mass (in kg, divide grams by 1000!)

• R = 8.314

• bigger molar mass = slower

• smaller molar mass = faster