A student recorded the following data for copper sulfate pentahydrate.
Weight of crucible and cover (after heating to constant weight), 28.120g
Weight of covered crucible plus sample, 31.020g
Weight of covered crucible plus sample after heating to constant weight, 30.020g
calculate the percentage of water in the hydrate. determine experimental error
%water in hydrate=48.5%
now what? how do i determine %water in hydrate from the given data? and then find the error?
Yes, determine the % from the data, then find error.
I don't understand how to determine the % from the data...
What's the 48.5%?
mass hydrated sample = 31.020-28.120 = ??
mass water = 31.020-30.020 = ??
%H2O = [mass water/mass hydrate ]*100 = ??
Check my numbers carefully.
34.48%, percentage water of hydrate, final answer?
right. 34.48% water.
I assume this is an experiment you did. Theoretical number is
[5*18.015/249.686]*100 = 36.08%.
Pretty good. Less than 5% error.
To determine the percentage of water in the hydrate, you need to calculate the mass of water lost during the heating process. Here's how you can do it step by step:
1. Calculate the mass of the crucible:
- Weight of crucible and cover (after heating to constant weight) = 28.120g
2. Calculate the mass of the hydrated copper sulfate:
- Weight of covered crucible plus sample = 31.020g
3. Calculate the mass of the anhydrous copper sulfate (after heating to constant weight):
- Weight of covered crucible plus sample after heating to constant weight = 30.020g
4. Calculate the mass of water lost during heating:
- Mass of water lost = Mass of crucible + Mass of hydrated copper sulfate - Mass of anhydrous copper sulfate
- Mass of water lost = 28.120g + 31.020g - 30.020g
- Mass of water lost = 29.120g - 30.020g = 1g
5. Calculate the percentage of water in the hydrate:
- % Water in hydrate = (Mass of water lost / Mass of hydrated copper sulfate) x 100%
- % Water in hydrate = (1g / 31.020g) x 100%
- % Water in hydrate ≈ 3.22%
Now let's move on to calculating the experimental error:
1. Determine the theoretical value of % water in the hydrate. This information is usually given or can be found in a reference source. In this case, the theoretical value is given as 48.5%.
2. Calculate the experimental error:
- Experimental error = |% Experimental - % Theoretical|
- Experimental error = |3.22% - 48.5%|
- Experimental error ≈ 45.28%
Therefore, the percentage of water in the copper sulfate pentahydrate is approximately 3.22%, and the experimental error is approximately 45.28%.