# Ksp Calculation

## Homework Statement

Hi,

I need to calculate the Ksp of Ag2CrO4 based on experimental data.

During the experiment, 1.25g of pure copper was placed in a 1.00 L solution of silver chromate. When the copper was extracted, only 1.24g remained.
Balanced chemical equation: Cu + Ag2CrO4 --> CuCrO4 + 2Ag

## The Attempt at a Solution

Here's what I did:

mole of copper = 0.01g / 63.546
= 1.57 * 10^-4

Since volume is 1.00 L, the number of moles is equal to the concentration.
There are 2 moles of Ag and 1 mole of CrO4 for every mole of copper, so:

Ksp = (1.57 * 10^-4) (3.15 * 10^-4) (3.15 * 10^-4)
= 1.56 * 10^-11

But this doesn't seem correct because the actual value is 1.1 * 10^-12.
This would give me a percentage error of over 1000%...

Any help would be much appreciated.

Related Biology and Chemistry Homework Help News on Phys.org
Borek
Mentor
Your approach looks correct and the answer seems to be consistent with the data given.

I don't like this question. I wonder how they extracted the copper. Solid left after reaction completed should weigh more, not less.

Ok, I thought I was doing it properly. I'm not sure why they made a question that produced a % error greater than 1000. Anyways, thanks Borek!

I'm currently working on this same question, lol, can you tell me if the answer to this question was marked correctly? I got the same answers with the same approach.. I know this thread is a year old ._.