Acetylene, a fuel used in welding torches, is comprised of 92.3% C and 7.7% H by mass. Find the molar mass if 1.10 g of acetylene occupies a volume of 1.00 L at 1.15 atm and 59.50 °C. • Use 0.08206 L atm mol K Use-273.15°C for absolute zero.