A beaker containing 3.400g of Hexane (C6H8) gas is combusted inside a cubic sealed chamber which measures 13.78 inches on each edge. The chamber's interior temperature was 75.00 degrees Fahrenheit before the combustion reaction. The container had an interior pressure of 1.000atm prior to the combustion. The air in the chamber was 20.000% oxygen by volume prior to the combustion reaction. After combustion, the interior temperature rose to 91.00 degrees Fahrenheit.

1. Determine the limiting reactant in the combustion reaction. How many leftover grams of the excess product remain? (should equal 0.3808g excess)

2. Determine the final pressure in the chamber after the combustion reaction in mmHg. Remember to account for the Oxygen used in the combustion and the gaseous products generated in the combustion. Assume that any water formed as a reaction product is vapor. (should equal 820.4mmHg)

Useful Facts: 1in = 2.54cm; 1000cm^3 = 1.000L; C= 5/9(F-32); PV=nRT; R=.08206L*atm/mol*K; 760mmHg = 1.0atm

I already figured out how to do the first one but the second question is confusing me so if someone could show me the work they used or explain to me how to answer it, that would be great.