Chapter 11, Problem 2STP

Interpretation Introduction

Interpretation:

Amount of copper metal needed to use up all of the ${\text{AgNO}}_3$ needs to be determined.

Concept introduction:

By using mole concept we can calculate the mass of metal.

Answer to Problem 2STP

(a) Mass of Cu is 18.669g

Explanation of Solution

Given:

Pure silver metal can be made using the reaction shown below,

$\text{Cu}\left(\text{s}\right)+\underset{}{{\text{AgNO}}_3}\left(\text{aq}\right)\to 2\text{Ag}\left(\text{s}\right){\text{ + Cu(NO}}_3{)}_2\left(\text{aq}\right)$

$\text{Cu}+\underset{100g}{{\text{AgNO}}_3}\to 2{\text{Ag + Cu(NO}}_3{)}_2$

Moles of ${\text{AgNO}}_3$ = $\frac{100}{170}=0.588\text{ mole}$

2 moles of ${\text{AgNO}}_3$ need one mole of Cu, so 0.588 moles of ${\text{AgNO}}_3$ need $\frac{0.588}{2}=0.294$

Thus, mass of Cu $0.284\times 63.5=18.669g$

Conclusion

Mass of Cu is 18.669g.