Chapter 6.1, Problem 5RQ

Interpretation Introduction

Interpretation: This is to be determined whether 3.89 g of nickel or 6.61 g of silver contains more atoms..

Concept Introduction: A mole of a substance is defined as the mass in grams of the substance that contains $6.02\times {10}^{23}$ units (atoms, molecules or ions of the substance). This mass is equal to the molar mass of the compound expressed in g.mol-1.

Answer to Problem 5RQ

The given weight of nickel will contain more atoms.

Explanation of Solution

The atomic masses are

Ni: $\text{58}\text{.693 g}{\text{.mol}}^{-1}$

Ag: $\text{107}\text{.868 g}{\text{.mol}}^{-1}$

  $\begin{array}{c}\text{Moles of Ni =}\frac{\left(\text{3}\text{.89 g}\right)}{\left(\text{58}\text{.693 g}{\text{.mol}}^{-1}\right)}\\ =0.06628\text{ mol}\end{array}$

  $\begin{array}{c}\text{Moles of Ag =}\frac{\left(\text{6}\text{.91 g}\right)}{\left(\text{107}\text{.868 g}{\text{.mol}}^{-1}\right)}\\ =0.06406\text{ mol}\end{array}$

It is known that 1 mole of any substance contains $6.02\times {10}^{23}$ units (atoms, molecules or ions) of the substance. Since there is more of the nickel sample than the silver sample (in terms of the number of moles), hence, the given weight of nickel will contain more atoms.

Conclusion

The given weight of nickel will contain more atoms.