Question

ch₄ + 2 o₂ → co₂ + 2 h₂o 11) if 2.59 moles of o₂ are used, how many grams of ch₄ are also used?

Explanation:

Step1: Find mole ratio of \( CH_4 \) and \( O_2 \)

From the reaction \( CH_4 + 2O_2
ightarrow CO_2 + 2H_2O \), the mole ratio of \( CH_4 \) to \( O_2 \) is \( \frac{1}{2} \).

Step2: Calculate moles of \( CH_4 \)

Given moles of \( O_2 = 2.59 \) mol. Let moles of \( CH_4 = n \). Using the ratio \( \frac{n}{2.59} = \frac{1}{2} \), so \( n = \frac{2.59}{2} = 1.295 \) mol.

Step3: Calculate molar mass of \( CH_4 \)

Molar mass of \( C = 12.01 \) g/mol, \( H = 1.008 \) g/mol. So molar mass of \( CH_4 = 12.01 + 4\times1.008 = 16.042 \) g/mol.

Step4: Calculate mass of \( CH_4 \)

Mass = moles × molar mass = \( 1.295 \times 16.042 \approx 20.77 \) g.

Answer:

\( \approx 20.8 \) grams (or more precisely \( \approx 20.77 \) grams)