Question #3e721

1 Answer
Oct 10, 2016

Answer:

#"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.