Concept:According to Avogadro's Law, reacting volumes of ideal gases at the same temperature and pressure perfectly mirror their stoichiometric molar coefficients from the balanced equation.
Formula:$$ \text{C}_2\text{H}_{4(g)} + 3\text{O}_{2(g)} \rightarrow 2\text{CO}_{2(g)} + 2\text{H}_2\text{O}_{(g)} $$
Solution:- First, write the balanced combustion equation for ethene (\( \text{C}_2\text{H}_4 \)).
- The equation shows a 1:3 ratio. Exactly 1 volume of ethene requires exactly 3 volumes of oxygen for complete combustion.
- We are given \( 500 \text{ dm}^3 \) of ethene.
- To find the required oxygen, multiply the ethene volume by 3.
- \( 500 \text{ dm}^3 \times 3 = 1500 \text{ dm}^3 \text{ of Oxygen} \).
Why other options are incorrect:- \( 500 \text{ dm}^3 \): Assumes an impossible 1:1 molar combustion ratio.
- \( 1000 \text{ dm}^3 \): Incorrectly assumes a 1:2 ratio.
- \( 2000 \text{ dm}^3 \): Incorrectly assumes a 1:4 ratio.
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