Aluminum reacts with excess copper(II) sulfate according to the unbalanced reaction
Al(s) + CuSO4(aq) −→
Al2(SO4)3(aq) + Cu(s)
If 2.21 g of Al react and the percent yield of
Cu is 40.8%, what mass of Cu is produced?
Answer in units of g.
I got 7.807423031 g of Cu.
Is that correct?
I didn't come up with that answer. Did you balance the equation?
2Al + 3CuSO4 ==> 3Cu + Al2(SO4)3
To determine the mass of Cu produced, we can use the given percent yield. However, before that, we need to balance the chemical equation:
2Al(s) + 3CuSO4(aq) → Al2(SO4)3(aq) + 3Cu(s)
Now, let's proceed to calculate the number of moles of Al:
Given: Mass of Al = 2.21 g
Molar mass of Al = 26.98 g/mol
Number of moles of Al = Mass of Al / Molar mass of Al
= 2.21 g / 26.98 g/mol
= 0.0819 mol
From the balanced equation, we can see that the mole ratio of Al to Cu is 2:3, which means for every 2 moles of Al, we expect to obtain 3 moles of Cu.
Using the mole ratio, we can calculate the theoretical yield of Cu:
Number of moles of Cu = (Number of moles of Al) × (3 moles of Cu / 2 moles of Al)
= 0.0819 mol × (3 mol / 2 mol)
= 0.1229 mol
Now, let's calculate the actual yield of Cu using the percent yield:
Given: Percent yield of Cu = 40.8%
Actual yield of Cu = (Percent yield / 100) × Theoretical yield
= (40.8% / 100) × 0.1229 mol
= 0.0502 mol
Finally, we can determine the mass of Cu produced:
Molar mass of Cu = 63.55 g/mol
Mass of Cu = Number of moles of Cu × Molar mass of Cu
= 0.0502 mol × 63.55 g/mol
= 3.19 g
Therefore, the correct mass of Cu produced is 3.19 g, not 7.807423031 g.
To determine the mass of Cu produced, we need to calculate the theoretical yield of Cu first.
1. Start by calculating the molar mass of aluminum (Al) and copper (Cu):
- Molar mass of Al = 26.98 g/mol
- Molar mass of Cu = 63.55 g/mol
2. Convert the mass of Al (2.21 g) to moles:
- Moles of Al = mass of Al / molar mass of Al
- Moles of Al = 2.21 g / 26.98 g/mol
3. Use the stoichiometry of the balanced equation to find the moles of Cu produced:
- According to the balanced equation, 1 mole of Al reacts to produce 1 mole of Cu.
- Moles of Cu = Moles of Al
4. Calculate the theoretical mass of Cu produced using the moles of Cu:
- Mass of Cu = Moles of Cu x molar mass of Cu
- Mass of Cu = Moles of Cu x 63.55 g/mol
5. Calculate the percent yield using the given percentage (40.8%):
- Percent Yield = (Actual Yield / Theoretical Yield) x 100
- Rearrange the equation to solve for Actual Yield:
- Actual Yield = (Percent Yield / 100) x Theoretical Yield
6. Substitute the given percent yield and theoretical yield into the equation from step 5.
Let's calculate the mass of Cu produced step-by-step:
Step 2: Moles of Al = 2.21 g / 26.98 g/mol
≈ 0.082 mol
Step 3: Moles of Cu = Moles of Al
= 0.082 mol
Step 4: Mass of Cu = Moles of Cu x molar mass of Cu
= 0.082 mol x 63.55 g/mol
≈ 5.21 g (theoretical yield of Cu)
Step 5: Actual Yield = (40.8 / 100) x 5.21 g
≈ 2.12 g
Therefore, the correct mass of Cu produced is approximately 2.12 g, not 7.81 g.