---
Just wondering if you could tell me what I am doing wrong for #8 on last years chem 150 test. The question is "What is the formula weight of nickel(II) nitrate?"
Heres what I did:
Nickel is 58.69 and there are 2 so I took (2)58.69. Nitrate is NO3 so Nitrogen is 14.01 and Oxygen is 16.00 and there are 3 so it would be 14.01+3(16). This leads me to:
2(58.69)+14.01+3(16) which gives me 179.39. This is the wrong answer...on the answer key the answer is 182.70. Just wondering what I did wrong. Thanks!
---
A lot of people trip up on this one. Remember, when there's a roman numeral after a metal, that tells you the charge of the metal cation, it does not tell you how many of that cation are in the balanced formula. For this one, the nickel has a +2 charge. Nitrate has a charge of -1, so to balance the charge of the formula, we need two NO3-1 for each Ni+2, Ni(NO3)2, so the formula weight of nickel(II) nitrate should be:
(58.69g/mol) + 2(14.007g/mol) + 6(15.999g/mol) = 182.70g/mol
Other questions, let me know...
No comments:
Post a Comment