Giwoong Choi
New member
Hello I have some questions to ask about stochiometry.
1. You take an aspirin tablet (a compound consisting solely of carbon, hydrogen and oxygen) with a mass of 1.00 g, burn it in air, and collect 2.20 g of carbon dioxide and 0.400 g water. The molar mass of aspirin is between 170 and 190 g/ mol. The molecular form of aspirin is: ?
a) C6H8O5 b) C9H804 c) C8H10O5 d) C10H6O4 e) nothing here
** additional question in this problem: I dont see why it makes sense when I had 1.00g originally and suddenly increases to 2.20 + 0.400 g. I thought according to the conservation of matter they should remain the same mass or less... where does additional mass come from?...
2. You heat 3.970 g of a mixture of Fe3O4 and FeO to form 4.195 g Fe2O3. The mass percent of FeO originally in the mixture was
a) 12.1% b) 28.7% c)71.3% d) 87.9% e) none
**I used mol to mol relationships and everything it still does not come out.
I have all the answers but I do not have the procedure... I am really curious how to deal with this kind of problem
3. Oxides of copper include CuO and Cu2O. You heat 1.51 g of one of these copper oxides in the absence of air and obtain 1,21g of Cu.
True/False : You must have had CuO.
** I cannot explain why.
Thank u!
1. You take an aspirin tablet (a compound consisting solely of carbon, hydrogen and oxygen) with a mass of 1.00 g, burn it in air, and collect 2.20 g of carbon dioxide and 0.400 g water. The molar mass of aspirin is between 170 and 190 g/ mol. The molecular form of aspirin is: ?
a) C6H8O5 b) C9H804 c) C8H10O5 d) C10H6O4 e) nothing here
** additional question in this problem: I dont see why it makes sense when I had 1.00g originally and suddenly increases to 2.20 + 0.400 g. I thought according to the conservation of matter they should remain the same mass or less... where does additional mass come from?...
2. You heat 3.970 g of a mixture of Fe3O4 and FeO to form 4.195 g Fe2O3. The mass percent of FeO originally in the mixture was
a) 12.1% b) 28.7% c)71.3% d) 87.9% e) none
**I used mol to mol relationships and everything it still does not come out.
I have all the answers but I do not have the procedure... I am really curious how to deal with this kind of problem
3. Oxides of copper include CuO and Cu2O. You heat 1.51 g of one of these copper oxides in the absence of air and obtain 1,21g of Cu.
True/False : You must have had CuO.
** I cannot explain why.
Thank u!