a chemist reacts 8.85g or iron with an excess oh hydrogen chloride to form hydrogen gas and iron(II)chloride.calculate the theoretical yield and the percentage yield of hydrogen if 0.27g H2 are collected
Write and balance the equation.
2Fe + 6HCl ==> 2FeCl3 + 3H2
Convert 8.85 g Fe to moles. moles = grams/molar mass.
Using the coefficients in the balanced equation, convert moles Fe to moles H2.
Now convert moles H2 to grams. grams = moles H2 x molar mass H2. This is the theoretical yield.
The above works most simple (not limiting reagent) stoichiometry problems. Print and save this for future reference.
%yield = (actual yield/theoretical yield)*100 = ??
To calculate the theoretical yield, we need to determine the balanced chemical equation for the reaction between iron and hydrogen chloride:
2 Fe + 6 HCl -> 3 H2 + 2 FeCl2
From the balanced equation, we can see that 2 moles of iron react with 6 moles of hydrogen chloride to produce 3 moles of hydrogen gas.
1. Calculate the number of moles of iron used:
Molar mass of iron (Fe) = 55.85 g/mol
Moles of iron = mass of iron / molar mass
Moles of iron = 8.85 g / 55.85 g/mol = 0.158 mol
2. Determine the theoretical yield of hydrogen:
From the balanced equation, we see that the stoichiometry is 2 moles of iron to 3 moles of hydrogen gas.
Moles of hydrogen gas = (moles of iron / 2) * 3
Moles of hydrogen gas = (0.158 mol / 2) * 3 = 0.237 mol
3. Calculate the theoretical yield of hydrogen gas:
Molar mass of hydrogen gas (H2) = 2 g/mol
Theoretical yield of hydrogen gas = moles of hydrogen gas * molar mass
Theoretical yield of hydrogen gas = 0.237 mol * 2 g/mol = 0.474 g
The theoretical yield of hydrogen gas is 0.474 g.
4. Calculate the percentage yield of hydrogen gas:
Percentage yield = (actual yield / theoretical yield) * 100
Percentage yield = (0.27 g / 0.474 g) * 100 ≈ 56.96%
The percentage yield of hydrogen gas is approximately 56.96%.
To calculate the theoretical yield and the percentage yield of hydrogen gas, we need to follow a step-by-step approach:
Step 1: Write and balance the chemical equation.
The balanced chemical equation for the reaction between iron and hydrogen chloride is:
Fe + 2HCl → FeCl2 + H2
Step 2: Calculate the molar mass of Fe and H2.
The molar mass of Fe is 55.845 g/mol.
The molar mass of H2 is 2.016 g/mol.
Step 3: Convert the mass of Fe to moles.
Using the molar mass of Fe:
moles of Fe = mass of Fe / molar mass of Fe
moles of Fe = 8.85 g / 55.845 g/mol
moles of Fe ≈ 0.1582 mol
Step 4: Determine the limiting reactant.
The limiting reactant is the one that will be fully consumed in the reaction and will determine the maximum amount of product that can be formed. In this case, hydrogen chloride is in excess, so iron is the limiting reactant.
Step 5: Calculate the moles of H2 formed.
From the balanced chemical equation, we know that 1 mole of Fe produces 1 mole of H2.
moles of H2 = moles of Fe ≈ 0.1582 mol
Step 6: Convert moles of H2 to mass.
Using the molar mass of H2:
mass of H2 = moles of H2 × molar mass of H2
mass of H2 = 0.1582 mol × 2.016 g/mol
mass of H2 ≈ 0.3186 g
So, the theoretical yield of hydrogen gas is approximately 0.3186 g.
Step 7: Calculate the percentage yield.
The percentage yield is the actual yield (0.27g) divided by the theoretical yield, multiplied by 100%.
percentage yield = (actual yield / theoretical yield) × 100
percentage yield = (0.27g / 0.3186 g) × 100
percentage yield ≈ 84.7%
Therefore, the theoretical yield of hydrogen gas is approximately 0.3186 g and the percentage yield is approximately 84.7%.