Ch 7 - Chemical Reactions and Chemical Quantities (Expectations)

What is the Law of Conservation of Mass and how does it apply to chemical reactions?

The Law of Conservation of Mass states that mass and number of atoms are conserved in a chemical reaction, meaning that the total mass of reactants equals the total mass of products.

Describe the significance of balanced chemical equations on both microscopic and macroscopic scales.

Balanced chemical equations reflect the conservation of atoms (microscopic) and allow the use of mole ratios for stoichiometric calculations (macroscopic).

How do mole ratios in stoichiometry help convert between different compounds in a reaction?

Mole ratios derived from balanced equations allow conversion between the amounts of reactants and products by relating coefficients to moles.

Explain the process to calculate the theoretical yield of a reaction.

Convert the mass of reactants to moles, use the stoichiometric ratios to find moles of product, and then convert moles of product to mass.

What steps are involved in determining the limiting reactant in a chemical reaction?

Convert reactant quantities to moles, use mole ratios to calculate possible product for each reactant, and identify the reactant producing the least product as the limiting reactant.

Outline the process to determine the excess reactant amount remaining after a reaction.

Calculate the amount of excess reactant used using stoichiometry, subtract from the initial amount to find the remaining quantity.

Define percent yield and its significance in chemical reactions.

Percent yield is the ratio of actual yield to theoretical yield, expressed as a percentage, indicating the efficiency of a reaction.

Compare and contrast actual yield and theoretical yield.

Theoretical yield is the maximum product amount calculated from reactants, whereas the actual yield is the measured amount obtained from the experiment.

What is molar mass and how is it related to atomic, molecular, and formula masses?

Molar mass is the mass in grams of one mole of a substance, equivalent to atomic mass in atoms, molecular mass in molecules, and formula mass in ionic compounds, all expressed commonly in g/mol.

Why is it important to use the smallest whole number ratios when writing chemical equations?

Using the smallest whole number ratios simplifies the representation of the reaction and maintains accurate stoichiometric relationships.

What determines the amount of product formed in a chemical reaction?

The limiting reactant, which is consumed completely during the reaction, determines the amount of product formed.

Explain the concept of stoichiometry.

Stoichiometry involves using balanced equations to calculate relative quantities of reactants and products in chemical reactions, based on mole ratios.

Differentiate between a reactant and a product in a chemical equation.

Reactants are substances consumed in a reaction (left side of equation), whereas products are substances formed (right side of equation).

What are the consequences of not balancing a chemical equation before performing stoichiometric calculations?

Unbalanced equations yield incorrect mole ratios, leading to faulty predictions of reactant and product quantities.

How does the conservation of mass apply when balancing a chemical equation?

Balancing ensures equal numbers of each type of atom on both sides of the equation, reflecting the conservation of mass from reactants to products.