Question

a chemist measures the amount of oxygen gas produced during an experiment. she finds that 68.1 g of oxygen gas is produced. calculate the number of moles of oxygen gas produced. be sure your answer has the correct number of significant digits.

Explanation:

Step1: Recall molar mass of O₂

Molar mass of \( O_2 \) is \( 32.00 \, \text{g/mol} \) (since atomic mass of O is \( 16.00 \, \text{g/mol} \), so \( 2 \times 16.00 = 32.00 \)).

Step2: Use moles formula

Moles \( n = \frac{\text{mass}}{\text{molar mass}} \). Given mass \( m = 68.1 \, \text{g} \), molar mass \( M = 32.00 \, \text{g/mol} \). So \( n = \frac{68.1}{32.00} \).

Step3: Calculate the value

\( \frac{68.1}{32.00} = 2.128125 \). Round to three significant digits (since 68.1 has three).

Answer:

2.13