cb8. 13.039Q Air and methane (CH4) combine at the inlet to an internal combustion engine. (Natural gas is largely methane - assume this natural gas consists of only methane.) The mole fraction of the methane in this mixture is 15%. The air-methane mixture enters the engine at 80 kPa and 20 C. The engine is a 4-stroke design and operates at 3000 RPM. The displacement of the engine is 5.0 L. Find the mass flow rate of the mixture as it enters the engine.