Chapter 15, Problem 55A

Interpretation Introduction

Interpretation: The number of moles present in $\text{1}\text{.0}\text{L}$ of water has to be calculated

Concept Introduction: The number of moles can be obtained from the mass in grams and molar mass. The number of moles is calculated by the formula,

$\text{Moles=}\frac{\text{Mass}}{\text{Molar}\text{mass}}$

Answer to Problem 55A

The number of moles of water is $\text{56}\text{mol}\text{.}$

Explanation of Solution

Given Information:

The density of water is $\text{1}\text{.0}\text{g/mL}\text{.}$

The volume of water is $\text{1}\text{.0}\text{L}\text{.}$

The molar mass of water is $\text{18}\text{g/mol}\text{.}$

Calculation:

The volume in liters is converted into grams,

$\text{1}\text{L=1000}\text{grams}$

The mass of water (in grams) is $\text{1000}\text{grams}\text{.}$

The moles of water is calculated as,

$\begin{array}{l}\text{Moles=}\frac{\text{Mass}}{\text{Molar}\text{mass}}\\ \text{Moles=}\frac{\text{1000}\text{grams}}{\text{18}\text{g/mol}}\\ \text{Moles=55}\text{.55}\text{mol}\end{array}$

The moles of water is $\text{55}\text{.55}\text{mol}\left(\text{or}\right)\text{56}\text{mol}\text{.}$

Conclusion

The number of moles of water is $\text{56}\text{mol}\text{.}$