Carbon monoxide gas and hydrogen gas react to form methanol vapour:
CO(g)+2H_2(g)->CH_3OH(g)
1.50*10^4 tonnes of carbon monoxide and the stoichiometric amount of hydrogen are reacted to form methanol at 250 deg. celsius and 10 MPa
a) Calculate the theoretical yield of methanol.
b) Calculate the percentage yield by weight of methanol if 1.67 * 10^4 tonnes of methanol are formed in this reaction.
how many moles of CO did you use?
You could get 3 times that many moles of CH3OH
convert that back to grams.
the yield is just
(what you got) / (what was possible) * 100%
To calculate the theoretical yield of methanol, we need to determine the limiting reactant first. The limiting reactant is the reactant that is completely consumed and determines the maximum amount of product that can be formed.
a) To find the limiting reactant, we compare the number of moles of carbon monoxide (CO) and hydrogen gas (H2) available to react. The balanced equation tells us that 1 mole of CO reacts with 2 moles of H2 to produce 1 mole of methanol (CH3OH).
Given:
Mass of CO = 1.50 × 10^4 tonnes
Molar mass of CO = 12.01 g/mol
First, we convert the mass of CO to moles:
Moles of CO = (Mass of CO) / (Molar mass of CO)
Substituting the given values:
Moles of CO = (1.50 × 10^4 tonnes) / (12.01 g/mol)
Next, we calculate the moles of H2 using the stoichiometric ratio:
Moles of H2 = 2 × Moles of CO
Now that we have the moles of both reactants, we can determine which one is the limiting reactant. The reactant that produces fewer moles of the product is the limiting reactant.
Moles of methanol produced (theoretical yield) = Moles of limiting reactant (CO)
Finally, we convert the moles of methanol to tonnes:
Theoretical yield of methanol = (Moles of methanol produced) × (Molar mass of methanol) / (10^6 g/tonne)
b) The percentage yield can be calculated by dividing the actual yield by the theoretical yield and then multiplying by 100.
Given:
Actual yield of methanol = 1.67 × 10^4 tonnes
Percentage yield = (Actual yield of methanol / Theoretical yield of methanol) × 100
To calculate the actual and theoretical yield, we use the formula:
Actual yield (in tonnes) = (Actual yield in moles) × (Molar mass of methanol) / (10^6 g/tonne)
Now, you can plug in the known values and follow these calculations to find the answers.