What is the percent yield of NaCl if 31.0 g of CuCl2 reacts with excess NaNO3 to produce 21.2 g of NaCl?
To calculate the percent yield of NaCl, we need to compare the actual yield of NaCl (which is 21.2 g) with the theoretical yield of NaCl. The theoretical yield is the maximum amount of NaCl that can be obtained based on the balanced chemical equation.
First, let's write the balanced chemical equation for the reaction:
CuCl2 + 2 NaNO3 -> 2 NaCl + Cu(NO3)2
According to the equation, 1 mole of CuCl2 reacts with 2 moles of NaNO3 to produce 2 moles of NaCl.
To determine the theoretical yield of NaCl, we need to calculate the number of moles of CuCl2 and then convert it to moles of NaCl using the stoichiometry of the balanced equation.
Step 1: Calculate the number of moles of CuCl2:
Molar mass of CuCl2 = (63.55 g/mol for Cu) + (2 x 35.45 g/mol for Cl)
= 63.55 g/mol + 70.90 g/mol
= 134.45 g/mol
Number of moles of CuCl2 = Mass of CuCl2 / Molar mass of CuCl2
= 31.0 g / 134.45 g/mol
≈ 0.2311 mol
Step 2: Use stoichiometry to convert moles of CuCl2 to moles of NaCl:
According to the balanced equation, 1 mole of CuCl2 produces 2 moles of NaCl.
Number of moles of NaCl = 2 x Number of moles of CuCl2
= 2 x 0.2311 mol
= 0.4622 mol
Step 3: Calculate the theoretical yield of NaCl:
Mass of NaCl = Number of moles of NaCl × Molar mass of NaCl
= 0.4622 mol × (22.99 g/mol for Na + 35.45 g/mol for Cl)
=0.4622 mol × 58.44 g/mol
≈ 27.01 g
Now that we have the theoretical yield of NaCl, we can calculate the percent yield:
Percent yield = (Actual yield / Theoretical yield) × 100
= (21.2 g / 27.01 g) × 100
≈ 78.45%
Therefore, the percent yield of NaCl is approximately 78.45%.
CuCl2 + 2NaNO3 ==> 2NaCl + Cu(NO3)2
mols CuCl2 = grams/molar mass
Using the coefficients in the balancaed equation,convert mols CuCl2 to mols NaCl formed.
Convert mols NaCl formed to grams. g = mols x molar mass. This is the theoretical yield (TY). The acuual yield (AY) is 2.12 g.
%yield = (AY/TY)*100 = ?