Question

1. mass-to-mass (single replacement reaction)

solid zinc (zn) reacts with aqueous copper(ii) nitrate ($\text{cu(no}_3\text{)}_2$) to produce zinc nitrate ($\text{zn(no}_3\text{)}_2$) and solid copper (cu).

• balanced equation: ____________
• if 25.0g of zinc (zn) is reacted, what mass (in grams) of copper (cu) is produced?
• mass of cu: ____________g

Explanation:

Step1: Balance the chemical equation

$\text{Zn}(s) + \text{Cu(NO}_3\text{)}_2(aq)
ightarrow \text{Zn(NO}_3\text{)}_2(aq) + \text{Cu}(s)$

Step2: Find molar masses

Molar mass of $\text{Zn} = 65.38\ \text{g/mol}$, Molar mass of $\text{Cu} = 63.55\ \text{g/mol}$

Step3: Calculate moles of Zn

$\text{Moles of Zn} = \frac{25.0\ \text{g}}{65.38\ \text{g/mol}} \approx 0.3824\ \text{mol}$

Step4: Relate moles Zn to Cu

From balanced equation, 1 mol Zn produces 1 mol Cu, so moles of Cu = 0.3824 mol

Step5: Calculate mass of Cu

$\text{Mass of Cu} = 0.3824\ \text{mol} \times 63.55\ \text{g/mol} \approx 24.3\ \text{g}$

Answer:

Balanced Equation: $\boldsymbol{\text{Zn}(s) + \text{Cu(NO}_3\text{)}_2(aq)
ightarrow \text{Zn(NO}_3\text{)}_2(aq) + \text{Cu}(s)}$
Mass of Cu: $\boldsymbol{24.3}$ g