Calculate mass of CH₄ consumed for the formation of 22 g CO₂. CH₄ + 2O₂ → CO₂ + 2H₂O

The correct answer is 8 g.

Let us solve this step-by-step using stoichiometry.

Step 1: Write the balanced chemical equation
The combustion of methane (${\mathrm{CH}}_4$) is represented by the following balanced chemical equation:
${\mathrm{CH}}_4+2O_2\to {\mathrm{CO}}_2+2H_{2}O$

From the balanced equation, we can see that 1 mole of methane (${\mathrm{CH}}_4$) reacts to produce 1 mole of carbon dioxide (${\mathrm{CO}}_2$).

Step 2: Calculate the molar masses of the reactants and products
- Molar mass of ${\mathrm{CH}}_4$ = 12 (Carbon) + 4 × 1 (Hydrogen) = 16 g/mol
- Molar mass of ${\mathrm{CO}}_2$ = 12 (Carbon) + 2 × 16 (Oxygen) = 44 g/mol

Step 3: Determine the moles of ${\mathrm{CO}}_2$ produced
We are given that 22 g of ${\mathrm{CO}}_2$ is formed. Let's find the number of moles:
$\text{Moles of}{\mathrm{CO}}_2=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{22}{44}=0.5\text{mol}$

Step 4: Find the moles of ${\mathrm{CH}}_4$ consumed
Since the mole ratio of ${\mathrm{CH}}_4$ to ${\mathrm{CO}}_2$ is 1:1, the moles of methane consumed is also equal to the moles of carbon dioxide produced:
$\text{Moles of}{\mathrm{CH}}_4=0.5\text{mol}$

Step 5: Calculate the mass of ${\mathrm{CH}}_4$ consumed
Now, we convert the moles of methane back into mass:
$\text{Mass of}{\mathrm{CH}}_4=\text{Moles}\times \text{Molar mass}=0.5\text{mol}\times 16\text{g/mol}=8\text{g}$

Therefore, the mass of methane consumed is 8 g.