Question

During a lab, you heat 1.04 g of a niso4 hydrate over a bunsen burner. after heating, the final mass of the dehydrated compound is 0.61 g. determine the formula of the hydrate and also give the full name of the hydrate.

Answer 1

The difference between the initial mass (1.04 g) and the final mass (0.61g) is the mass of water present in the sample:

1.04 g - 0.61 g = 0.43 g

Divide by the molar mass of water: 18.01 g / mol to obtain the number of moles of water:

0.43 g / 18.01 g / mol = 0.0239 moles

Calculate the number of moles of dehydrated NiSO4

Number of moles = mass in grams / molar mass

molar mass of NiSO4 = 154.75 g/mol

number of moles NiSO4 = 0.61 g / 154.75 g/mol = 0.00394 moles

Now determine the molar ratio water to NiSO4: 0.0239 / 0.00394 = 6.07 ≈ 6

Then, the formula of the hydrate product is NiSO4 · 6 H2O.

Use the prefix hexa (6) to name the compound: Nickel(II) sulfate hexadydrate