Question

Question #3e721

Answer 1

`"928.4 g"`

Explanation:

You know that chalcopyrite is `34.63%` copper by mass, which essentially means that every `"100 g"` of chalcopyrite contain `"34.63 g"` of copper.

That is what percent concentration by mass tells you. That `%` sign means that you're looking at `"100 g"` of a compound.

So, you know that you get `"34.63 g"` of copper for every `"100 g"` of chalcopyrite, and that the sample contains `"321.5 g"` of copper.

You can use the ore's percent concentration by mass as a conversion factor to help you calculate the mass of ore that would contain that many grams of copper

`321.5 color(red)(cancel(color(black)("g Cu"))) * "100 g ore"/(34.63color(red)(cancel(color(black)("g Cu")))) = color(green)(bar(ul(|color(white)(a/a)color(black)("928.4 g ore")color(white)(a/a)|)))`

The answer is rounded to four sig figs.