The heat of combustion of butane is 2658 kl. A cylinder of LPG gas (containing only butane) is assumed to contain 14.2 kg of butane. If a normal family needs 18000 kJ of energy per day for cooking, how long the cylinder will last?

Explanation

To solve the problem step by step, we will follow these calculations:

### Step 1: Write the combustion reaction of butane.
The balanced chemical equation for the combustion of butane (C₄H₁₀) is:
\[ \text{C}_4\text{H}_{10} + 13/2 \text{O}_2 \rightarrow 4 \text{CO}_2 + 5 \text{H}_2\text{O} \]
The heat of combustion (ΔH) for this reaction is given as -2658 kJ per mole of butane.
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