A greenish blue salt known to be composed of copper and chloride ions is dissolved in DI water. Aluminum metal is used to reduce the copper ions to metallic copper, which is collected, dried and weighed. If the origanal sample has a mass 1.362g and the collected copper has a mass .635g, what is the empirical formula of bthe compound?
CuClx + Al ==> Cu +_ AlClx (not balanced)
mass CuClx = 1.362
-mass Cu = 0.635
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mass Cl = 0.727
mols Cu = 0.635/63.5 = about 0.01
mols Cl = 0.727/35.5 = about 0.02
Find the ratio of Cu to Cl and write as the empirical formula. If you don't see that immediately, divide both numbers by the same small number to get whole numbers.
To find the empirical formula of the compound, we need to determine the ratio of the elements in the compound based on the given information.
1. Determine the molar mass of copper (Cu):
The atomic mass of copper (Cu) is approximately 63.55 g/mol.
2. Calculate the number of moles of copper (Cu):
Number of moles = Mass / Molar mass
Number of moles of copper = 0.635 g / 63.55 g/mol = 0.01 mol
3. Determine the number of moles of chlorine (Cl):
Since the compound contains chloride ions, the number of moles of copper should be equal to the number of moles of chloride ions.
4. Determine the mass of chlorine (Cl):
Mass of chlorine = Mass of original sample - Mass of copper collected
Mass of chlorine = 1.362 g - 0.635 g = 0.727 g
5. Calculate the number of moles of chlorine:
Number of moles = Mass / Molar mass
Number of moles of chlorine = 0.727 g / 35.45 g/mol = 0.02 mol
6. Determine the ratio of copper to chlorine:
The ratio of moles is approximately 1:1 for both copper and chlorine.
7. Determine the empirical formula:
The empirical formula is the simplest whole number ratio of the elements. In this case, the ratio is 1:1.
Therefore, the empirical formula of the compound is CuCl.