An unknown hydrate of copper (II) oxalate is to be identified in the lab. The following data was collected by a student:

Mass of crucible 23.776 g
Mass of crucible + hydrate 24.889 g
Mass of crucible + anhydrate 24.530 g

Thank you

To identify the unknown hydrate of copper (II) oxalate, we can use the concept of calculating the percent composition of the hydrate.

First, let's calculate the mass of the hydrate by subtracting the mass of the empty crucible from the mass of the crucible with the hydrate:

Mass of hydrate = Mass of crucible + hydrate - Mass of crucible

Mass of hydrate = 24.889 g - 23.776 g = 1.113 g

Next, let's calculate the mass of the anhydrate by subtracting the mass of the empty crucible from the mass of the crucible with the anhydrate:

Mass of anhydrate = Mass of crucible + anhydrate - Mass of crucible

Mass of anhydrate = 24.530 g - 23.776 g = 0.754 g

Now, let's calculate the mass of water lost during the dehydration process:

Mass of water lost = Mass of hydrate - Mass of anhydrate

Mass of water lost = 1.113 g - 0.754 g = 0.359 g

To calculate the percent composition, we need to find the percent of water in the hydrate:

Percent of water = (Mass of water lost / Mass of hydrate) x 100

Percent of water = (0.359 g / 1.113 g) x 100 = 32.28%

Finally, we can determine the formula of the unknown hydrate by using the molar mass of copper (II) oxalate and the percent of water.

The molar mass of copper (II) oxalate (CuC2O4) can be calculated using the atomic masses from the periodic table.

Atomic mass of Cu = 63.55 g/mol
Atomic mass of C = 12.01 g/mol
Atomic mass of O = 16.00 g/mol

Molar mass of CuC2O4 = (63.55 g/mol) + (2 x 12.01 g/mol) + (4 x 16.00 g/mol)
= 128.57 g/mol

Since the percent of water is 32.28%, the percent of copper (II) oxalate is 100% - 32.28% = 67.72%.

Now, let's calculate the mass of copper (II) oxalate in the hydrate:

Mass of copper (II) oxalate = (Mass of hydrate) x (Percent of copper (II) oxalate / 100)

Mass of copper (II) oxalate = 1.113 g x (67.72 / 100) = 0.752 g

Now, let's calculate the number of moles of copper (II) oxalate in the hydrate:

Number of moles of CuC2O4 = (Mass of copper (II) oxalate) / (Molar mass of CuC2O4)

Number of moles of CuC2O4 = 0.752 g / 128.57 g/mol = 0.00585 mol

From the stoichiometry of copper (II) oxalate, we know that there is one mole of CuC2O4 per one mole of water in the hydrate.

Therefore, the formula of the unknown hydrate is CuC2O4 · H2O.