Question

A chemist mixes 3.90 g of chlooform with 19.4 g of acetyl bromide And 83.4 g of heptane. Calculate the percent by mass of each component of the solution. Be sure each of your answer entries has the correct number of significant digits.

Answer 1

1) Define the equation for calculating mass percent.

`\text{Percent by mass=}\frac{\text{mass of solute}}{\text{mass of solution}}\cdot100`

2) The mass percent of chloroform

`\text{Percent by mass of Chloroform=}\frac{3.90\text{ g of chloroform}}{3.90\text{ g + 19.4 g + 83.4 g }}\cdot100=\text{ 3.66\% chloroform}`

The mass percent of chloroform is 3.66% chloroform.

3) The mass percent of acetyl bromide

`\text{Percent by mass of acetyl bromide=}\frac{19.4\text{ g acetyl bromide}}{3.90g\text{ + 19.4g + 83.4g}}\cdot100=\text{ 18.2\%}`

The mass percent of acetyl bromide is 18.2% acetyl bromide

4) The mass percent of heptane

`\text{Percent by mass of heptane=}\frac{83.4g\text{ of heptane}}{3.90g\text{ +19.4g +83.4g}}\cdot100=\text{ 78.2\% of heptane}`

The mass percent of heptane is 78.2% of heptane