A volume of 2.46 l of a mixture of ethane and methane gases on complete combustion at 300 K and 1 atm produced 3.69 l of carbon dioxide. Find out the amount of heat evolved on burning the 2.46 l of ga

Question

A volume of 2.46 l of a mixture of ethane and methane gases on complete combustion at 300 K and 1 atm produced 3.69 l of carbon dioxide. Find out the amount of heat evolved on burning the 2.46 l of gaseous mixture. The heats of combustion of ethane and methane are -1560 and -890 kJ per mole, respectively. (R = 0.082 l-atm/K-mol)

TestHub · Accepted Answer

Let x l ethane and y l methane. x + y = 2.46 and 2x + y = 3.69, so x = y = 1.23 l. Molar volume = 0.082 × 300 = 24.6 l/mol, so each gas is 1.23/24.6 = 0.05 mol. Heat = 0.05 × (1560 + 890) = 0.05 × 2450 = 122.5 kJ. This is option (a).

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