# Question #ddb73

Mar 6, 2014

This is a gas law stoichiometry problem because you are in conditions other than STP.

Begin by determining how many moles of $C {O}_{2}$ you can theoretically produce based upon stoichiometry.

43.0 g $C {H}_{4}$ / 16 g $C {H}_{4}$ = 2.687 moles $C {H}_{4}$
(16 g is the molar mass of $C {H}_{4}$)

Convert moles $C {H}_{4}$ to moles $C {O}_{2}$ using the mole ratio from the balanced chemical equation.

2.687 moles $C {H}_{4}$ x 1 mole $C {O}_{2}$ / 1 mole $C {H}_{4}$ = 2.687 moles $C {O}_{2}$

Now use the moles in the ideal gas law to convert to volume at non STP values for temperature and pressure.

P = 795 mmHg / 760 mmhg = 1.04 atm
V = ???
n = 2.687 moles $C {O}_{2}$
R = 0.0821 atm L/mole K
T = 85 C + 273 = 358 K

PV = nRT converts to v = nrt/P

V = 2.687 moles (0.0821 atm L/mole K) ( 358 K) / 1.04 atm.
all units cancel except Liters (L)

V = 75.9 L $C {O}_{2}$