Question

Copper(II) chloride hydrate, also known as copper chloride hydrate, is the inorganic compound with the chemical formula CuCl2 . x(H2O), where x can range from 1 to 7. A 2.060 g sample of copper (II) chloride hydrate was dissolved in 50.0 mL of deionized water. The concentration of copper (II) ion in the solution was determined spectrophotometrically using the equation from the calibration curve, was 0.200 M. Determine the formula of the copper (II) chloride hydrate.

Answer 1

Answer:

CuCl₂·4H₂O

Explanation:

First we calculate the moles of copper (II) ion in the solution, using the given volume and concentration:

• 50.0 mL ⇒ 50.0/1000 = 0.05 L

• 0.05 L * 0.200 M = 0.01 mol Cu⁺²

For each Cu⁺² mol there's also one CuCl₂ mol.

We convert 0.01 CuCl₂ moles into grams, using its molar mass:

• 0.01 CuCl₂ mol * 134.45 g/mol = 1.344 g

That means that out of the 2.060 g of the sample, 1.344 g are of CuCl₂. This means that there are (2.060 - 1.344) 0.716 g of water.

We convert those 0.716 g of water to moles:

• 0.716 g ÷ 18 g/mol = 0.04 mol H₂O

There are four times as many H₂O moles as there are CuCl₂ moles. This means the formula is CuCl₂·4H₂O