Limiting Reactant and Excess Reactant Calculations
Chemistry ⇒ Stoichiometry and Chemical Calculations
Limiting Reactant and Excess Reactant Calculations starts at 11 and continues till grade 12.
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A reaction requires 2 moles of A for every 3 moles of B. If you have 4 moles of A and 9 moles of B, which reactant is in excess?
Context: 10.0 g of Ca reacts with 10.0 g of O2 to form CaO. Which is the limiting reactant? (Atomic masses: Ca = 40, O = 16)
Context: 2Na + H2SO4 → Na2SO4 + H2. If 4.6 g Na reacts with 9.8 g H2SO4, which is the limiting reactant? (Na = 23, H = 1, S = 32, O = 16)
Context: 5.0 g of Mg reacts with 10.0 g of HCl to form MgCl2 and H2. Which is the limiting reactant? (Mg = 24, H = 1, Cl = 35.5)
A reaction requires 2 moles of A for every 3 moles of B. If you have 4 moles of A and 9 moles of B, which reactant is in excess?
Context: 10.0 g of Ca reacts with 10.0 g of O2 to form CaO. Which is the limiting reactant? (Atomic masses: Ca = 40, O = 16)
Context: 2Na + H2SO4 → Na2SO4 + H2. If 4.6 g Na reacts with 9.8 g H2SO4, which is the limiting reactant? (Na = 23, H = 1, S = 32, O = 16)
Context: 5.0 g of Mg reacts with 10.0 g of HCl to form MgCl2 and H2. Which is the limiting reactant? (Mg = 24, H = 1, Cl = 35.5)
Which of the following is a correct statement about limiting reactants? (1) The limiting reactant is always the one with the lowest mass. (2) The limiting reactant is always the one with the lowest number of moles. (3) The limiting reactant is the one that produces the least amount of product. (4) The limiting reactant is always the one with the highest molar mass.
Which of the following is NOT a reason for a reactant to be in excess? (1) It is cheaper. (2) It is more reactive. (3) It is required in a smaller stoichiometric ratio. (4) It is less available.
Which of the following is NOT a step in determining the limiting reactant? (1) Calculating the moles of each reactant. (2) Comparing the mole ratio of reactants used to the balanced equation. (3) Calculating the mass of each product. (4) Identifying the reactant that produces the least amount of product.
Which of the following is the correct sequence for solving a limiting reactant problem? (1) Convert masses to moles, (2) Use mole ratio, (3) Identify limiting reactant, (4) Calculate product formed.
Fill in the blank: After a reaction is complete, the amount of excess reactant left can be calculated by subtracting the amount __________ from the initial amount.
Fill in the blank: In a chemical reaction, the reactant that is not completely consumed is called the __________ reactant.
Fill in the blank: The amount of product formed in a reaction is limited by the amount of __________ reactant.
Fill in the blank: The reactant that determines the maximum amount of product that can be formed is called the __________ reactant.
True or False: The excess reactant determines the theoretical yield of a reaction.
True or False: The excess reactant is always present in greater mass than the limiting reactant.
True or False: The limiting reactant can be identified by calculating the amount of product formed from each reactant and choosing the smallest value.
True or False: The limiting reactant is always the one with the smallest number of moles.
