Chapter 6, Problem 7STP

Interpretation Introduction

Interpretation: The mass percent of carbon in the table sugar sucrose needs to be determined.

Concept introduction: The mass percent of any atom in the compound can be calculated as follows:

  $\%m=\frac{n\times \text{Atomic mass of atom}}{\text{Molar mass of compound}}\times 100\%$

Here, n is number of atoms.

Answer to Problem 7STP

Correct Answer: Option B. 42.10%.

Explanation of Solution

The given compound is sucrose with formula ${\text{C}}_{\text{12}}{\text{H}}_{\text{22}}{\text{O}}_{\text{11}}$ .

The molar mass of C, H and O is 12.01 g/mol, 1.008 g/mol and 15.999 g/mol respectively.

Thus, molar mass of compound will be:

  $M=12\left(12.01\right)+22\left(1.008\right)+11\left(15.999\right)=342.3\text{ g/mol}$

Now, the mass percent of carbon can be calculated as follows:

  $\begin{array}{l}\%m=\frac{n\times C}{{\text{C}}_{\text{12}}{\text{H}}_{\text{22}}{\text{O}}_{\text{11}}}\times 100\%\\ =\frac{12\left(12.01\right)}{342.3}\times 100\%\\ =42.10\%\end{array}$

Thus, the mass percent of carbon in table sugar is $42.10\%$ .

Conclusion

Thus, the correct option is B that is 42.10%.