In the combustion of butane, 72g of water is given out, how much butane is taken

Consider the complete combustion of butane, the amount of butane utilized to produce 72.0 g of water is ________ xx 10^(-1) g. (in nearest integer)

In a 12 litre mixture of acid and water , acid 30% ,Then how much water is taken out so that acid becomes 40%

The heat of combustion of butane is 2880kJ" "mol^(-1) . What is the heat liberated by buring 1 kg of butane in excess of oxygen supply?

a. A cylinder of gas is assumed to contain 11.2 kg of butane. If a normal family needs 20000kJ of energy per day for cooking, how long will the cylinder last? Given that the heat of combustion of butane is 2658 kJ mol^(-1) . b. If the air supply of the burner is insufficient (i.e. you have a yellow instead of a blue flame), a portion of the gas escape without combustion. Assuming that 33% of the gas is wasted due to this inefficiency, how long would the cylinder last?