Chapter 5, Problem 1SAQ

Carbon tetrachloride has a chlorine - to- carbon mass ratio of 11.8:1. If a simple of carbon tetrachloride contains 35 g of chlorine what mass of carbon does it contain?

a. 0.34 g c

b.1.0 g c

c. 3.0 g c

d. 11.8 g c

Interpretation Introduction

Interpretation: Mass of carbon present in a sample of carbon tetrachloride which contains $35g$ of chlorine is to be determined.

Concept Introduction:

The elements in a chemical reaction combine in a mixed ratio to form the compound.

According to law of constant composition, all the samples of the given compound have same proportions of their constituent elements. The mass ratio of chlorine-to-carbon is:

$\text{Mass ratio}=\frac{\text{Mass of chlorine}}{\text{Mass of carbon}}$

Answer to Problem 1SAQ

Correct Answer: option c is the correct answer.

Explanation of Solution

Reason for correct option:

The mass ratio of chlorine-to-carbon is $11.8:1$. Calculate the mass of carbon as follows:

$\text{Mass ratio}=\frac{\text{Mass of chlorine}}{\text{Mass of carbon}}$

Substitute $35\text{ g}$ for mass of the chlorine and $11.8:1$ for mass ratio in the above expression as follows:

$\frac{11.8}{1}=\frac{\text{35 g}}{\text{Mass of carbon}}$

Rearrange the above expression as follows:

$\begin{array}{c}\text{Mass of carbon}=\frac{\text{35 g}}{11.8}\\ =2.96\text{ g}\\ =3.0\text{ g}\end{array}$

The mass of carbon is $3.0\text{ g C}$. Thus, option(c) is correct.

Reasons for incorrect options:

Option (a) is incorrect because according to the above calculation, the mass of carbon $\text{0}\text{.34 g C}$ cannot be obtained. So, this answer is not correct.

Option (b) is incorrect because the mass of carbon $\text{1}\text{.0 g C}$ cannot be obtained according to the above calculation. So, this answer is not correct.

Option (d) is incorrect because according to the above calculation, the mass of carbon $\text{11}\text{.8 g C}$ cannot be obtained. So, this answer is not correct.

Hence, options (a), (b), and (d) are incorrect.