Stoichiometry of Formulas and Equations

Vocabulary flashcards covering the fundamental concepts of stoichiometry, including the mole, molar mass, chemical formulas, and reaction yields as presented in Chapter 3.

Mole (mol)

The amount of a substance that contains the same number of entities as there are atoms in exactly $12\,g$ of carbon-12.

Entities

Refers to atoms, ions, molecules, formula units, or electrons — in fact, any type of particle.

Avogadro’s number ($N_A$)

The number of entities in one mole, abbreviated as $N_A$ and equal to $6.022 \times 10^{23}$ entities.

Molar Mass ($M$)

The mass of a mole of a substance's entities (atoms, molecules, or formula units), expressed in units of $g/mol$.

Empirical Formula

The simplest formula for a compound that shows the lowest whole number of moles and the relative number of atoms of each element present.

Molecular Formula

A formula that shows the actual number of atoms of each element in a molecule of a compound; it is a whole-number multiple of the empirical formula.

Combustion Analysis

A method used to determine the amounts of carbon and hydrogen in a combustible organic compound by burning it in an excess of pure $O_2$ and measuring the $CO_2$ and $H_2O$ produced.

Chemical Equation

A representation that uses formulas to express the identities and quantities of substances involved in a physical or chemical change.

Law of Conservation of Mass

The scientific principle used in the process of balancing chemical equations, requiring the same number and type of each atom to appear on both sides of the equation.

Stoichiometrically Equivalent Molar Ratios

Quantitative relationships from a balanced equation used as conversion factors to calculate the amounts of reactants and products.

Limiting Reactant

The reactant that is completely used up in a reaction and limits the amount of product that can form.

Excess Reactant

The reactant that is not limiting and remains left over after the reaction is complete.

Theoretical Yield

The amount of product calculated using the molar ratios from the balanced equation.

Actual Yield

The amount of product actually obtained from a reaction, which is usually less than the theoretical yield.

Percentage Yield

The ratio of the actual yield to the theoretical yield multiplied by 100%, calculated as $\frac{\text{actual yield}}{\text{theoretical yield}} \times 100\%$.