JAMB - Chemistry (1983 - No. 41)
A jet plane carrying 3,000 kg of ethane burns off all the gas forming water and carbondioxide. if all the carbondioxide is expelled and all the water formed is condensed and kept on board the plane, then the gain in weight is
1,800 kg
900 kg
600 kg
2, 400 kg
1, 200 kg
Объяснение
2\(C_2H_6 + 7O_2 →4CO_2 + 6H_2O\)
addition of oxygen causes weight gain, expelled \(CO_2\) results in weight loss
for oxygen added;
2moles \(C_2H_6\) = 7moles \(O_2\)
2(30)g \(C_2H_6\) = 7(2)(16)g \(O_2\)
3000kg \(C_2H_6\) = X kg \(O_2\)
cross multiplying X = 11200kg
for \(CO_2\) expelled;
2moles \(C_2H_6\) = 4moles \(CO_2\)
2(30)g \(C_2H_6\) = 4(44)g \(CO_2\)
3000kg \(C_2H_6\) = Y kg \(CO_2\)
cross multiplying Y = 8800kg
since X > Y, the plane has a net weight gain.
Net weight gain = X - Y = 11200-8800 = 2400kg.