Question

zn + s → zns
17 g of zn and excess s react in a sealed container.
what is the theoretical yield of zns?
? g zns

Explanation:

Step1: Calculate moles of Zn

Molar mass of Zn is 65.38 g/mol. Moles of Zn = mass / molar mass = \( \frac{17\ g}{65.38\ g/mol} \approx 0.260\ mol \).

Step2: Determine moles of ZnS

From the reaction \( \text{Zn} + \text{S}
ightarrow \text{ZnS} \), the mole ratio of Zn to ZnS is 1:1. So moles of ZnS = moles of Zn = 0.260 mol.

Step3: Calculate mass of ZnS

Molar mass of ZnS: Zn (65.38 g/mol) + S (32.07 g/mol) = 97.45 g/mol. Mass of ZnS = moles × molar mass = \( 0.260\ mol \times 97.45\ g/mol \approx 25.3\ g \).

Answer:

25.3 (approximate value, depending on molar mass precision)