Question

1. use your scratch paper to work the rr track for this problem: how many moles of na₂(so₃) are 279 grams? round to the tenths place.

Explanation:

Step1: Calculate molar mass of \( \text{Na}_2\text{SO}_3 \)

Molar mass of \( \text{Na} = 22.99 \, \text{g/mol} \), \( \text{S} = 32.07 \, \text{g/mol} \), \( \text{O} = 16.00 \, \text{g/mol} \).
Molar mass \( = 2\times22.99 + 32.07 + 3\times16.00 \)
\( = 45.98 + 32.07 + 48.00 = 126.05 \, \text{g/mol} \)

Step2: Use moles formula (\( \text{moles} = \frac{\text{mass}}{\text{molar mass}} \))

Mass \( = 279 \, \text{g} \), molar mass \( = 126.05 \, \text{g/mol} \)
\( \text{moles} = \frac{279}{126.05} \approx 2.213 \)

Step3: Round to tenths place

\( 2.213 \approx 2.2 \)

Answer:

\( 2.2 \)