Based on the data provided, the empirical formula of the compund is CuCl2.6H20 and the percentage mass of copper is 24.8%.
Empirical formula is a formula showing the simplest ratios in which elements in the compund are combined.
From the data provided:
Mass of Hydrated Copper chloride = 1.00 g
Mass of dehydrated Copper chloride = 20.976 - 20.43 = 0.546 g
Mass of Water = 21.43 - 20.976 = 0.454 g
Mass of Copper = 0.248 g
Masd of Chlorine = 1.00 - (0.454 + 0.248) = 0.298
Mole ratio:
Cu = 0.248/64 = 0.004
Cl = 0.298/35.5 = 0.008
H2O = 0.454/18 = 0.025
Dividing with the smallest value:
Cu = 0.004/0.004 = 1
Cl = 0.008/0.004 = 2
H2O = 0.025/0.004 = 6
Therefore;
Empirical formula = CuCl2.6H20
Percentage mass of copper = 0.248/1.00 × 100%
Percentage mass of copper = 24.8%
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