Posted by Jennifer on Saturday, March 31, 2007 at 8:44am.
Hw many minutes will it take a current of 31.559 Amperes to deposit 1.722 grams of aluminum?
I believe it to be 6.505 minutes
Is this correct? If not, I'll post my work. Thanks
I found 9.757 minutes.
Ok, here's my work, I just plugged in numbers to another problem, I hope this makes sense:
Convert grams to moles:
1.722g x 1g/26.981538mol =.0638214174mol
.0638214174mol x 2 = .1276428349 mol e-
.1276428349 mol e- x 965000 = 12317.53C
t = 12317.53C/ 31.559
t = 6.505
If you don't mind, can you explain where I went wrong. thanks
I tried copying this so I could mark the lines for errors but for some reason I can't copy it. I'll just explain it and you follow along.
#1. You used 2 for the number of electrons. Al is trivalent and the reaction is Al3+
+ 3e = Al. That is a major source of your error.
#2. I used 96485 for coulombs in an ampere instead of 96,500. If you are carrying so many decimal places as you show, then you should not round to 96,500; however, this is a minor source of error.
#3. You don't show the conversion to minutes, but I see your work reflects that.
So your 0.12764 will be 0.19146
and that times 96485 = 18,473
and that divided by 31.559 = 585.34 sec and that divided by 60 = 9.76 min.
Check my arithmetic
I didn't obey all the rules for significant figures. You should go through and round the final answer to the right number of s.f. Since 1.722 g has 4 s.f. I think you are allowed 4 in the answer if you use 96,485 and not 96,500.
Also, I forgot to mention that you have one too many zeros on 96500 but that is just a typo since the number doesn't reflect that extra zero.
Yeah I had a lot of errors. Thanks for explaing that.
Answer this Question
More Related Questions
- Chem - How many minutes will it take a current of 66.049 Ampères to deposit 86....
- Chemistry - A solution of H2SO4 was electrolyzed using the inert platinum ...
- science - If the half-life of a 20.0g is known to be 24 minutes, how long will ...
- Chem - How many grams of nickel can be produced by passing a current of 15.0A ...
- math - 6. If each of eight biology classrooms is in use for 5 hours and 15 ...
- Stitistics - An oil change company advertises that they can change the oil in ...
- math - Vanessa typically works 8 hours per day in a normal 5 day work week. Last...
- statistics - the average patient lasts 45 minutes on the tilt table. the current...
- AP Chemistry - An unknown metal M forms a soluble compound, M(NO3)2. A solution ...
- Physical Science - Here are some half-lives for different isotopes of bismuth (...