Free Theoretical and Percentage Yield MCQs with Answers

• A. the maximum mass of product calculated from the balanced equation and the limiting reactant
• B. the mass of product actually obtained in the laboratory
• C. always equal to the mass of the limiting reactant
• D. the mass of the excess reactant left over

Explanation: Theoretical yield is a calculation, assuming the reaction goes to completion with no losses and no side reactions, and it is the standard…

• A. 125 per cent
• B. 80 per cent
• C. 5 per cent
• D. 20 per cent

Explanation: Percentage yield is actual divided by theoretical multiplied by 100, so 20 divided by 25 multiplied by 100 gives 80 per cent.

• A. some product is lost during filtration and transfer
• B. side reactions produce unwanted products
• C. the balanced equation was written incorrectly
• D. the reaction is reversible and does not go to completion

Explanation: Physical losses, competing side reactions and reversibility are all genuine reasons why a real yield falls short.

• A. 100 g
• B. 44 g
• C. 40 g
• D. 56 g

Explanation: The equation shows a one to one ratio, so 1 mole of CaCO3 gives 1 mole of CaO, whose molar mass is 40 + 16, that is 56 g.

• A. 63.6%
• B. 77.8%
• C. 87.5%
• D. 92.5%

Explanation: Four grams of hydrogen is 2 moles and 32 g of oxygen is 1 mole, which is exactly the 2 to 1 ratio the equation requires, so neither is in…

• A. 20%
• B. 25%
• C. 45%
• D. 80%

Explanation: Percentage yield is actual divided by theoretical multiplied by 100, so 20 over 25 multiplied by 100 gives 80 per cent.

• A. 20 g
• B. 25 g
• C. 30 g
• D. 40 g

Explanation: Rearranging the percentage yield formula, the theoretical yield is the actual yield multiplied by 100 and divided by the percentage, so 20…

• A. 40g
• B. 43.6g
• C. 45g
• D. 41.4g

Explanation: Percentage yield = actual yield/theoretical yield x 100, so theoretical yield = 24 g x 100/55 = 43.64 g, approximately 43.6 g.

• A. Practical yield
• B. Theoretical yield
• C. Actual yield
• D. NOT

Explanation: The balanced chemical equation gives the stoichiometric maximum product that can form when the limiting reactant reacts completely, called…

• A. 1565.72 kg
• B. 965.46 kg
• C. 2759.81 kg
• D. 2846.12 kg

Explanation: To calculate the amount of H3PO4 produced, we need to first find the amount of tetraphosphorus decaoxide (P4O10) produced and then the…

• A. Rate constant
• B. Enthalpy
• C. Temperature
• D. Yield

Explanation: The rate of reaction can be determined by a number of methods, including physical and chemical methods.

• A. Percentage
• B. Actual
• C. Theoretical
• D. Combination of all of these

Explanation: The actual yield is obtained from the reaction. Theoretical yield is calculated from a balanced chemical equation.

• A. Percentage
• B. Actual
• C. Theoretical
• D. All of these options are correct

Explanation: The efficiency of a chemical reaction is determined by the percentage yield, that is the ratio of theoretical yield to actual yield…

• A. 60%
• B. 58%
• C. 90%
• D. 50%

Explanation: The above question states that 1-bromopropane i.e CH3-CH2-CH2-Br has a molar mass of 123g is being prepared from 10g of 1-propanol i.e…

• A. Theoretical yield
• B. Practical yield
• C. Percentage yield
• D. All of above

Explanation: Stoichiometry uses the balanced chemical equation to calculate how much product can theoretically form from given amounts of…

• A. 2.0 X27/150 x100
• B. 2.0/10 X 2 X 27/150 X 100
• C. 2.0/10 X 27/1500 X 100
• D. 2.0/10 X 150/3 X 27 X 100

Explanation: Mass of aluminum in formula: 2×27=54 gMolar mass of Al₂S₃: 2×27+3×32=54+96=150 g54/150x100=36%