Question

If 305 L of gas is collected at -65 degree C and 675 kpa, what would the volume be at STP? Explain.

Answer 1

first calculate no. of mole of gas at given condition

Use ideal gas equation for calculation of mole of gas

Ideal gas equation

PV = nRT             where, P = atm pressure= 675 kpa = 6.415 atm,

V = volume in Liter = 305 L

n = number of mole = ?

R = 0.08205L atm mol^-1 K^-1 =Proportionality constant = gas constant,

T = Temperature in K = -65⁰C = 273.15+ (-65) = 208.15 K

We can write ideal gas equation

n = PV/RT

Substitute the value

n = (6.415X 305 ) / (0.08205 X 208.15) = 114.56 mole

now calculate volume of gas at STP

We know that PV = nRT

V = nRT/P

n = 114.56 mole,

T = 273.15 K,

P= 1 atm,

R = 0.08205 L atm mol^-1 K^-1 ( R = gas constant)

V = ?

Substitute these value in above equation.

V = 114.56 X 0.08205 X 273.15/ 1 = 2567.5 L

Volume of gas at STP = 2567.5 L