Answer:
170 dm³ (2 significant figures)
Explanation:
CH₄ + 2O₂ → CO₂ + 2H₂O
We need to find how much 'volume' of Oâ‚‚ is required to burn 56 g of CHâ‚„.
Let's take the ratios of the two gases only.
CHâ‚„ : 2Oâ‚‚ (in terms of moles the ratio is 1:2)
56g : x dm³
Mr of CHâ‚„ : Volume of oxygen at rtp
Find the Mr of CHâ‚„.
Mr of CH₄ = 12 + (1 × 4) = 16
We know that 1 mole of any gas occupies 24 dm³ at room temperature and pressure (rtp). We have to find the volume of oxygen, there are 2 moles of oxygen, so 2 moles of gas will occupy:
2 × 24 = 48 dm³
56g : x dm³
 16 : 48 dm³
16x = 56 × 48
16x = 2688
x = [tex]\frac{2688}{16}[/tex]
x = 168 dm³
∴ the minimum volume of oxygen gas, at room temperature and pressure required to completely burn 56g of methane gas is 170 dm³