# Question d14a0

##### 1 Answer
Sep 21, 2017

$\text{45 lbs}$

#### Explanation:

You know that the chocolate bars contain 22.0% by mass pecans. This means that you get $\text{22.0 kg}$ of pecans for every $\text{100 kg}$ of chocolate bars.

Your first step here will be to use the given percent concentration by mass as a conversion factor to calculate how many kilograms of chocolate bars will contain $\text{4.5 kg}$ of pecans.

4.5 color(red)(cancel(color(black)("kg pecans"))) * "100 kg chocolate bars"/(22.0color(red)(cancel(color(black)("kg pecans")))) = 225/11color(white)(.)"kg chocolate bars"#

Now, in order to convert this to pounds, you need to use the fact that

$\text{1 kg " ~~ " 2.2046 lbs}$

You will end up with

$\frac{225}{11} \textcolor{red}{\cancel{\textcolor{b l a c k}{\text{kg"))) * "2.2046 lbs"/(1color(red)(cancel(color(black)("kg")))) = color(darkgreen)(ul(color(black)("45 lbs}}}}$

The answer is rounded to two sig figs, the number of sig figs you have for the mass of pecans.