Chapter U4.25, Problem 2E

(a)

Interpretation Introduction

Interpretation:

The mole ratio of ${\text{AgNO}}_{\text{3}}\text{to}\text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_2$ should be predicted.

Concept Introduction:

The amount of the substance that contains the same number of particles or atoms or molecules is termed as mole.

Answer to Problem 2E

The mole ratio of ${\text{AgNO}}_{\text{3}}\text{to}\text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_2$ is 2:1.

Explanation of Solution

The given balanced chemical equation is represented as follows:

  $\text{Cu}\left(s\right){\text{+2AgNO}}_{\text{3}}\left(aq\right)\to \text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\left(aq\right)+2\text{Ag}\left(s\right)$

According to the reaction, 2 moles of ${\text{AgNO}}_{\text{3}}$ react with 1 mole of $\text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}$ thus, The mole ratio of ${\text{AgNO}}_{\text{3}}\text{to}\text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_2$ is 2:1.

(b)

Interpretation Introduction

Interpretation:

The mole ratio of ${\text{AgNO}}_{\text{3}}\text{to}\text{Ag}$ should be predicted.

Concept Introduction:

The amount of the substance that contains the same number of particles or atoms or molecules is termed as mole.

Answer to Problem 2E

The mole ratio of ${\text{AgNO}}_{\text{3}}\text{to}\text{Ag}$ is 1:1.

Explanation of Solution

The given balanced chemical equation is represented as follows:

  $\text{Cu}\left(s\right){\text{+2AgNO}}_{\text{3}}\left(aq\right)\to \text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\left(aq\right)+2\text{Ag}\left(s\right)$

According to the reaction, 2 moles of ${\text{AgNO}}_{\text{3}}$ react with 2 moles of $\text{Ag}$ thus, the mole ratio of ${\text{AgNO}}_{\text{3}}\text{to}\text{Ag}$ is 1:1.

(c)

Interpretation Introduction

Interpretation:

The moles of AgNO₃and moles of Cu(NO₃)₂ required should be predicted.

Concept Introduction:

The amount of the substance that contains the same number of particles or atoms or molecules is termed as mole.

Answer to Problem 2E

12 moles of ${\text{AgNO}}_{\text{3}}$ are required and 6 moles of $\text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_2$ are produced.

Explanation of Solution

The given balanced chemical equation is represented as follows:

  $\text{Cu}\left(s\right){\text{+2AgNO}}_{\text{3}}\left(aq\right)\to \text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\left(aq\right)+2\text{Ag}\left(s\right)$

According to the reaction, 1 mole of Cu reacts with 2 moles of ${\text{AgNO}}_{\text{3}}$ thus, the moles of ${\text{AgNO}}_{\text{3}}$ needed to completely react with Cu are calculated as follows:

  $\begin{array}{c}\text{1}\text{mol}\text{Cu}\to \text{2}\text{mol}{\text{AgNO}}_{\text{3}}\\ 6\text{mol}\text{Cu}\to \left(\text{6}\times \text{2}\right)\text{mol}{\text{AgNO}}_{\text{3}}\\ \to 12\text{mol}{\text{AgNO}}_{\text{3}}\end{array}$

Now, the moles of copper nitrate produced are calculated as follows:

  $\begin{array}{c}\text{1}\text{mol}\text{Cu}\to 1\text{mol}\text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\\ 6\text{mol}\text{Cu}\to \left(\text{6}\times 1\right)\text{mol}\text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\\ \to 6\text{mol}\text{Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\end{array}$

(d)

Interpretation Introduction

Interpretation:

The moles of Ag and moles of Cu required should be predicted.

Concept Introduction:

The amount of the substance that contains the same number of particles or atoms or molecules is termed as mole.

Answer to Problem 2E

The moles of Ag and moles of Cu required 0.2781 and 0.13095 are respectively.

Explanation of Solution

The number of moles of Ag in 30 g are calculated as follows:

  $\begin{array}{c}\text{Number}\text{of}\text{moles}\text{of}\text{Ag}=\frac{\text{Given}\text{mass}\text{of}\text{Ag}}{\text{Molar}\text{mass}\text{of}\text{Ag}}\\ =\frac{\text{30}\text{g}}{107.8682\text{g/mol}}\\ \text{Number}\text{of}\text{moles}\text{of}\text{Ag}=0.2781\text{mol}\end{array}$

According to the reaction,

  $\begin{array}{c}2\text{mol}\text{Ag}\to 1\text{mol}\text{Cu}\\ 1\text{mol}\text{Ag}\to \left(\frac{1}{2}\right)\text{mol}\text{Cu}\\ \text{0}\text{.2781}\text{mol}\text{Ag}\to \left(\frac{1}{2}\times \text{0}\text{.2781}\right)\text{mol}\text{Cu}\\ \to 0.13905\text{mol}\text{Cu}\end{array}$

Thus, 0.13905 Moles of Cu are required.