You have a 99.0 L vessel at 240.0 K that contains 75.0 g of CH4 gas and 35.0 g of CO gas, what is the total pressure of the system (in atm)?

Answer 1

mols CH4 = g/molar mass = ?
mols CO = g/molar mass = ?
total mols = n = mols CH4 + moles CO
Then PV = nRT. You know V, n, R and T. Substitute and solve for P in atm.
For P in atm use R = 0.08206 L*atm/mol*K
Post your work if you get stuck.