Chapter 3: Chemical Reactions and Reaction Stoichiometry

This flashcard set covers essential concepts in chemistry, including Stoichiometry, Chemical Reactions, and the relationships between Reactants, Products, and Balancing Equations. It also includes key topics like States of Matter, Avogadro’s Number, Empirical and Molecular Formulas, and the principles of Limiting Reactants and Excess Reagents.

Stoichiometry

Involves ratios between reactants and products in chemical reactions.

Chemical Equations

Represent chemical reactions with reactants on the left and products on the right, separated by arrows.

Balancing Equations

Ensures the same number of elements on each side without changing coefficients.

Reactants

The starting materials (on the left of the arrow)

Products

The ending materials (on the right of the arrow)

Symbols in chemical equations

Include (g) for gas, (l) for liquid, (s) for solid, and (aq) for aqueous.

Combination reaction

Two or more substances react to form one product.

Example: A + B —> C

Decomposition reaction

One substance breaks down into two or more substances.

Example: C —> A + B

Combustion reactions

Involve rapid reactions producing flame, often with oxygen, resulting in CO₂ and H₂O

Formula weight (FW)

Sum of atomic weights in a chemical formula.

Percent composition

Determines the percentage of each element in a compound's mass.

Equation: (Total Mass of Element Percent)/ (Molecular Mass) x 100

Avogadro’s Number

6.02 × 10²³ atoms or molecules is the number of particles in one mole (mol)

Molar mass

Mass of 1 mol of a substance, equivalent to the formula weight.

Determining Empirical Formulas

Steps include assuming 100g sample, converting percentages to grams, then to moles, and calculating mole ratios.

Percent Yield

Compares actual yield to theoretical yield to find the efficiency of a reaction.

Equation: (Actual yield / Theoretical yield) x 100

Theoretical yield

The maximum amount of product that can be made

Actual yield

The amount one actually produces and measures.

Limiting reactants

The reactant in the smallest stoichiometric amount that determines the amount of product formed. What you will run out of first.

Excess reagent

What is left over.