Chapter 6, Problem 12STP

Interpretation Introduction

Interpretation: The M in formula MO₂ needs to be identified, if it contains 40.1 % of oxygen by mass.

Concept Introduction: Mass percentage is the way to calculate the percentage of each element in the given molecular compounds. The mathematical expression of mass percentage can be shown as:

  $\text{Mass percentage = }\frac{\text{Number of element × mass of element}}{\text{molar mass of compound}}\times 100\%$

Answer to Problem 12STP

The metal with 47.8 g/mol is Titanium.

Explanation of Solution

Given information:

Mass percentage of O = 40.1 %

Mass percentage of O = 40.1 %

Molar mass of O = 16.0 g/mol

1 mole of MO2 = 2 moles of O

Mass percentage of M= 100 − 40.1 = 59.9 %

  $\begin{array}{l}\frac{\text{(2×16}\text{.00g/mol)}}{\text{ 40}\text{.1}}\text{= }\frac{x}{\text{59}\text{.9}}\\ \frac{x}{\text{59}\text{.9}}\text{=0}\text{.798}\\ x\text{ = 47}\text{.8g/mol = Ti}\end{array}$

The metal with 47.8 g/mol is Titanium.

Conclusion

The metal with 47.8 g/mol is Titanium.