Problems on energy balances 1. Natural gas comprising CH4 87.5%, C2H6 7.0%, and C3H8 5.5% by volume is burned with air (21 vol% 02 and 79% N2) with an excess-air percentage of 10% in an adiabatic combustor. Determine the outlet temperature of the gaseous products. Chemical Rxns: Given that the heat capacities of these substances (species) are assumed to be constant throughout the process. The reference temperature of the feed is taken to be 298 K CH, = 35.4 kJ/(kg-mol-K) CH, = 52.6 kJ/(kg-mol-K) CzH, = 74.3 kJ/(kg-mol-K) CO, = 50.0 kJ/(kg-mol-K) H,O (g) = 38.5 kJ/(kg-mol-K) 0, = 33.1 kJ/(kg-mol-K) N = 31.3 kJ/(kg-mol-K)