When 3.00g of calcium chloride were reacted in an excess of silver nitrate, 6.4g of AlCl
were produced. What was the percent yield in this reaction?
is this from a CA lesson?
CaCl2 + 2AgNO3 → 2AgCl + Ca(NO3)2
3.00g CaCl2 is 0.027 moles
So you expect 0.054 moles of AgCl
6.4g AgCl is 0.0446 moles
so the yield is 0.446/0.054 = 82.7%
To calculate the percent yield of a reaction, you need to compare the actual yield (the amount of product obtained in the experiment) to the theoretical yield (the maximum amount of product that can be obtained, calculated using stoichiometry).
In this case, we know that 3.00g of calcium chloride (CaCl2) reacted to form 6.4g of aluminum chloride (AlCl3). We need to find the percent yield.
First, we need to determine the molar masses of CaCl2 and AlCl3:
- The molar mass of CaCl2 = 40.08 g/mol (atomic mass of calcium = 40.08 g/mol + 2 x atomic mass of chlorine = 35.45 g/mol)
- The molar mass of AlCl3 = 133.34 g/mol (atomic mass of aluminum = 26.98 g/mol + 3 x atomic mass of chlorine = 35.45 g/mol)
Next, we can calculate the number of moles of CaCl2 and AlCl3:
- Moles of CaCl2 = Mass of CaCl2 / Molar mass of CaCl2 = 3.00 g / 110.98 g/mol = 0.027 moles
- Moles of AlCl3 = Mass of AlCl3 / Molar mass of AlCl3 = 6.4 g / 133.34 g/mol = 0.048 moles
Now, we need to determine the stoichiometric ratio between CaCl2 and AlCl3 in the balanced equation. The balanced equation for this reaction is:
3 CaCl2 + 2 AgNO3 → AlCl3 + 3 Ca(NO3)2
From the balanced equation, we can see that the ratio is 3:1. This means that for every 3 moles of CaCl2, you should get 1 mole of AlCl3. Therefore, the theoretical yield of AlCl3 can be calculated as:
Theoretical yield of AlCl3 = Moles of CaCl2 x (1 mole of AlCl3 / 3 moles of CaCl2) = 0.027 moles x (1/3) = 0.009 moles
To convert the theoretical yield from moles to grams, we can use the molar mass of AlCl3:
Theoretical yield of AlCl3 = Moles of AlCl3 x Molar mass of AlCl3 = 0.009 moles x 133.34 g/mol = 1.20 g
Finally, we can calculate the percent yield using the formula:
Percent yield = (Actual yield / Theoretical yield) x 100%
In this case:
Actual yield = 6.4 g
Theoretical yield = 1.20 g
Percent yield = (6.4 g / 1.20 g) x 100% ≈ 533.33%
Therefore, the percent yield in this reaction is approximately 533.33%.