Chemistry question

lou :) · Posted: Fri Nov 10, 2006 7:54 pm Post subject: hellpp meee please!!!

I have a question to do and i have absoloutely no idea where to begin. It is about a titration but its unlike any question that i've seen and i dont know how to apply what i know to it:

(COOH)2.'N'H2O + 2NAOH

i have to figure out the value of N. I was told it is a whole number between 1 and 4 but thats all. I also have to comlpete it as if i was planning a titration. Do you know how to figure out how much of the acid is needed and therefore estimate the titre then working out the mr from that. I would really appreciate any help. Thanks.

Lawsen Lew · Member Joined: 11 Nov 2006 Posts: 15

3 CuO(s) + 2Al (s) -------> Al2O3 (s) + 3 Cu(s)

How many g of Al(s) to completely react with the CuO(s)? This is a simple stoichoimetry problem. It is not very difficult. The periodic chart and a good calculator is all you need. I have my giant, old TI-92 and I have the newest HP series, too. I graduated with my BS in earth science. I am very happily unemployed with my place, awaiting to be moved back to my mom's living room, repatriated back to my mom's family. So much for that.

From the periodic table:
Cu 63.546 g/mol
O 15.9994 g/mol
Al 26.98154 g/mol

The reaction might be endothermic? That is not part of the question

CuO is 79.5454 g/mol=63.546 g/mol+ 15.9994 g/mol

12 g CuO * (1 mol CuO/79.5454 g) * ( 2 mol Al/ 3 mol CuO) * (26.98154 g Al/ 1 mol Al)=2.7 g Al

We will need 2.7 g Al to react completely with 12 g CuO.

I still have not earned my Ph.D, yet. I hope this works?

Lawsen Lew
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