Chapter U4.83, Problem 3E

Interpretation Introduction

Interpretation:

The reason for 0.10 M CuCl₂to have greater density m/V as compared to 0.10 M KCl must be explained.

Concept introduction:

Density of a solution is the amount of mass present per unit volume of the solution.

Answer to Problem 3E

As molecular weight of CuCl₂ is greater as compared to KCl, 0.10 M CuCl₂ has greater density m/V as compared to 0.10 M KCl.

Explanation of Solution

0.10 M CuCl₂ solution means there is 0.1 mol CuCl₂ in 1 L solution.

Molecular weight of CuCl₂ is calculated from atomic mas of Cu and Cl as follows:

  $\begin{array}{l}M=\left(63.5+2\times 35.5\right)\\ =63.5+71\\ =134.5\text{ g/mol}\end{array}$ .

Thus amount of CuCl₂in 1L solution will be:

  $m=n\times M=0.1\times 134.5g=\text{13}\text{.45 g}$

Similarly,

0.10 M KCl solution means there is 0.1 mol KCl in 1 L solution.

Molecular weight of KCl will be:

  $M=\left(39+35.5\right)=74.5\text{ g/mol}$

Thus amount of KClin 1L solution will be:

  $m=n\times M=0.1\times 74.5g=7.45g$

Conclusion

So, 0.10 M CuCl₂ has greater density m/V as compared to 0.10 M KCl.