Question

You bought some copper oxide on-line. You thought you were buying copper II oxide (CuO) but you actually bought copper I oxide (Cu2O). How much more copper did you get per 100g of compound purchase?

Answer 1

MW of Cu = 63.546  g/mol

MW of CuO = 79.545 g/mol

MW of Cu2O = 143.09 g/mol

copper in CuO per 100 g:

% of Cu in CuO = mass of Cu / mass of CuO * 100% = 63.546 /79.545 * 100 = 79.886%

so, 100 grams --> 79.886*100 = 79.886 grams of Copper were required

but we got:

Cu2O, so

% of Cu in Cu2O = mass of Cu / mass of C2uO * 100% = 2*63.546 /143.09 * 100 = 88.819 %

then

in 100 g of Cu2O, we have --> 88.819 g of Copper

compare:

79.886 vs 88.819

extra amount of Copper (per 100 grams of sample) = 88.819 -79.886 = 8.933 g of Copper extra (per 100 grams of sample)