Chapter 12.3, Problem 2PE

Interpretation Introduction

Interpretation

The mass percent of naphthalene in the given solution should be calculated. 

Concept introduction

Percent by mass: It is the ratio of solute mass to the solution mass which finally multiplied by $\text{100}$. The formula for percent by mass calculation is as follows,

$\begin{array}{l}\text{Percent mass =}\frac{\text{Mass}\text{of}\text{solute}}{\text{Mass of solution}}\text{×100\%}\\ \text{Mass of solution = Mass of solute + Mass of solvent}\end{array}$

Moles: One mole is equivalent to the mass of the substance consists same number of units equal to the atoms present in $\text{12}\text{g}$ of ${}^{\text{12}}\text{C}$.

From given mass of substance moles could be calculated by using the following formula,

$\text{Moles}\text{of}\text{substance }\text{= }\frac{\text{Given}\text{mass}\text{of}\text{substance}}{\text{Molecular}\text{mass}}$

Mass: It is the quantitative measure of a substance. The amount of matter present in substance is expressed as mass. The $S.I.$ unit of mass is $kg$.