Stoichiometry, % yield, Limiting Reactants

What is stoichiometry?

• A method for measuring temperature in chemical reactions.

• The branch of chemistry that deals with the calculation of reactants and products in chemical reactions based on the conservation of mass.

• A technique used to separate mixtures into their individual components.

• The study of the rates of chemical reactions.

What is the theoretical yield?

• The theoretical yield is the maximum amount of product that can be produced from a given amount of reactants, based on stoichiometric calculations.

• The theoretical yield is the amount of product actually obtained from a reaction.

• The theoretical yield is the minimum amount of reactants needed for a reaction to occur.

• The theoretical yield is the amount of product that can be produced without any reactants.

What is the significance of the coefficients in a balanced chemical equation?

• They indicate the temperature at which the reaction occurs.

• They represent the physical state of the reactants and products.

• They indicate the ratio of moles of reactants and products involved in the reaction.

• They show the energy changes during the reaction.

What is the role of excess reactant in a chemical reaction?

• It is the reactant that is completely consumed first.

• It is present in a quantity greater than necessary to completely react with the limiting reactant, ensuring that the reaction goes to completion.

• It is the reactant that determines the amount of product formed.

• It has no significant role in the reaction.

Define limiting reactant.

• The reactant that is present in excess in a chemical reaction.

• The substance that is completely consumed in a chemical reaction, limiting the amount of product that can be formed.

• The reactant that determines the rate of the reaction.

• The product that is formed in the largest quantity.

Calculate the percent yield if the theoretical yield is 50g and the actual yield is 40g.

• 70%

• 75%

• 80%

• 85%

If you have 10 moles of A and 15 moles of B in the reaction A + 2B → C, how many moles of C can be produced?

• 3 moles of C can be produced, as B is the limiting reactant.

• 10 moles of C can be produced, as A is the limiting reactant.

• 5 moles of C can be produced, as A is the limiting reactant.

• 15 moles of C can be produced, as there is an excess of B.

What is the molar mass of water (H2O)?

• 16.00 g/mol

• 18.02 g/mol

• 20.00 g/mol

• 22.00 g/mol

How do you identify the limiting reactant in a reaction?

• By calculating the moles of each reactant and determining which one produces the least amount of product.

• By identifying the reactant with the highest molecular weight.

• By measuring the temperature change during the reaction.

• By adding excess of one reactant to see which one runs out first.

If 10g of a reactant produces 8g of product, what is the percent yield?

• 60%

• 70%

• 80%

• 90%