Question

what will be the mass of angydrous Alum left over if one starts with 100.00 g of hydrated Alum?

please can you explain what fraction do I need to use. Based on the given information I can find the %theoretical of water in angydrous Alum. But I still don't understand how to solve for left over.

Answer 1

%H2O = (12*molar mass H2O/molar mass KAl(SO)4)2.12H2O)*100 = ??
% anhydrous alum = 100 - %H2O
fraction anydrous alum = % anhydrous alum/100.

grams anhydrous alum in 100 g alum = 100g x fraction anhydrous alum.


By the way, there is no water, theoretical or otherwise, in anhydrous alum.