The Water loss by the sample, and the percent by weight of water in the unknown hydrates is 34.78%H2O.
which of the ten possible hydrates are the most likely ones to be your unknown based on the percent by weight?
To determine which of the ten possible hydrates is the most likely to be your unknown based on the percent by weight of water, we can compare the given percentage (34.78%) with the known percentages of water in each hydrate. Here's how you can calculate this:
1. List the ten possible hydrates and their respective formulas.
- For example: CuSO4·5H2O, MgSO4·7H2O, FeCl3·6H2O, etc.
2. Calculate the molecular weight of each hydrate by adding the atomic weights of the elements in the formula.
- For instance, the molecular weight of CuSO4·5H2O is calculated as:
Molecular weight = (atomic weight of Cu) + (atomic weight of S) + (4 * atomic weight of O) + (5 * atomic weight of H) + (2 * atomic weight of O)
3. Determine the weight of water in each hydrate by multiplying the number of H2O molecules in the formula by the atomic weight of water (18.015 g/mol).
4. Calculate the percentage by weight of water in each hydrate by dividing the weight of water by the molecular weight of the hydrate and multiplying by 100.
- For example, if the weight of water in a hydrate is 90 g and the molecular weight of the hydrate is 250 g/mol, the percentage by weight of water would be: (90 / 250) * 100 = 36%.
5. Compare the percentage by weight of water calculated in step 4 with the given percentage (34.78%).
The hydrate with the percentage closest to the given percentage is the most likely one to be your unknown.
By following these steps, you should be able to identify the most likely hydrate based on the percent by weight of water.