Two minerals that contain copper are chalcopyrite, cufes2, and chalcocite, cus. what mass of chalcocite would contain the same mass of copper as is contained in 250 pounds of chalcopyrite?

150 g of chalcocite (Cu) contain the same mass of Cu than 250 pounds of chalcopyrite.

Explanation:

First, we need to pass 250 pound to the metric system using the relationship 1 lbs = 453g. Then,

Secondly, we look for the mass of copper in 1.13 x 10⁵ grams of CuFeS₂, knowing that there are 63.5g of Cu in 183.5 g of CuFeS₂ (molar masses).

Finally, we find the mass of CuS that contains 99.5 g of Cu, knowing that 63.5 g of Cu are found in 95.5 g of CuS (molar masses).

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !