I conducted a lab in which I had to calculate the number of moles of water heated off from copper sulfate. I first weighed copper sulfide in a beaker to in order to get the amount needed to begin the heating of it. If the beaker was wet at the beginning of the experiment for the initial mass of the beaker, how would that affect the experimentally determined number of molecules of hydrate. Increase, decrease, or no affect?

1 answer

Actually you could get all three under different scenarios. I don't think that is the intent of the question.
To show just one scenario:
1. Water + beaker = xx grams.
2. Add CuSO4.5H2O = 2.0 + xx grams.
Subtracting gives me 2.0 g CuSO4.5H2O as long as none of the water evaporated