A reaction requires 22.4 L of gas at STP. You have 25.0 L of gas at 101.5 kPa and 373 K. Which of the following statements is true? (Use the ideal gas law: PV = nRT where R = 8.31 L-kPa/mol-K.)

Question

You will have enough gas

You will have excess gas

You do not have enough gas

Answer 1

STP is 101.325 kPa pressure and 273K temperature

Also, at STP, 1 mol of an ideal gas = 22.4 L

Since the question states that 22.4 L are needed at STP, we know that ONE MOLE is needed. Now, the question is, how many moles are actually present?

V = 25.0 L

P = 101.5 kPa

T = 373K

n = ?

R = 8.31 L-kPa/Kmol

Solving the ideal gas law for n (moles) and comparing that to 1 mole, we have...

n = PV/RT = (101.5)(25.0)/(8.31)(373)

n = 0.82 moles of gas. THIS IS NOT ENOUGH as it is less than the ONE mole required.