Chapter 3: Chemical Stoichiometry Vocabulary Flashcards

A comprehensive collection of vocabulary flashcards based on Zumdahl Chemistry Chapter 3: Chemical Stoichiometry.

Stoichiometry

The study of quantities of materials consumed and produced in chemical reactions.

Mass spectroscopy

An analytical technique used to determine the relative masses of atoms and molecules.

Mass spectrometer

An instrument that vaporizes and ionizes a sample, directing positive ions through an accelerating electric field and magnetic field to separate them onto a detector plate based on mass.

Carbon-12 atomic mass standard

The baseline reference for atomic mass, where ${}^{12}\text{C}$ is assigned a mass of exactly $12$ atomic mass units ($\text{u}$).

Average atomic mass

The weighted average mass of an element's naturally occurring isotopes, calculated as $\sum (\text{Fraction of isotope})(\text{Relative atomic mass of isotope})$.

Mole

The number equal to the number of carbon atoms in exactly $12\,\text{g}$ of pure ${}^{12}\text{C}$, containing $6.022 \times 10^{23}$ units.

Avogadro's number

The quantity $6.022 \times 10^{23}$, representing the number of units in one mole of any substance.

Molar mass

The mass in grams of one mole of a given substance.

Mass percent of an element

The percentage of a compound's total mass contributed by a constituent element, calculated as $\left( \frac{\text{mass of element in } 1\,\text{mol of compound}}{\text{mass of } 1\,\text{mol of compound}} \right) \times 100\%$.

Empirical formula

The chemical formula of a compound that expresses the simplest whole-number ratio of the atoms present.

Molecular formula

The actual formula of a compound showing the exact number of each atom present, represented as $(\text{empirical formula})_n$ where $n$ is an integer.

Combustion analysis apparatus

A device used to determine the mass percent of carbon and hydrogen in an organic compound by burning the sample in $\text{O}_2(g)$ and capturing produced $\text{H}_2\text{O}$ in an absorber like $\text{Mg(ClO}_4)_2$ and $\text{CO}_2$ in an absorber like $\text{NaOH}$.

Balanced chemical equation

A chemical reaction equation containing equal numbers of each type of atom on both reactant and product sides, showing the overall molar ratios of species involved.

Mole ratio

The ratio of coefficients between any two species in a balanced chemical equation, used to convert moles of one substance to moles of another.

Stoichiometry mole island diagram

A conversion map illustrating pathways between mass, volume of gas at STP, particles, and moles for reactants and products using stoichiometric ratios.

Limiting reactant

The reactant in a chemical reaction that is completely consumed first, thereby limiting the amount of product that can be formed.

Stoichiometric mixture

A mixture of reactants combined in exact relative molar proportions specified by the balanced chemical equation, leaving no excess reactants after reaction.

Theoretical yield

The maximum calculated mass of product that can form when the limiting reactant is completely consumed.

Actual yield

The measured mass of product actually recovered from a laboratory experiment.

Percent yield

A measure of reaction efficiency calculated as $\left( \frac{\text{actual yield}}{\text{theoretical yield}} \right) \times 100\%$.