Chemical Energetics and Stoichiometry Flashcards

Vocabulary practice flashcards covering chemical energetics, equilibrium, acids and bases, stoichiometry, and organic chemistry families.

Exothermic Reaction

A chemical reaction where heat is released, bonds are made, and the enthalpy change ($AH$) is negative, resulting in warmer surroundings.

Endothermic Reaction

A chemical reaction where energy is taken in to break bonds, the enthalpy change ($AH$) is positive, and the surroundings become colder.

Dynamic Equilibrium

A state in a chemical reaction where the forward and backward reactions occur at the same rate, resulting in no overall change and stable external appearance.

Acid

A group of soluble chemicals that produce hydrogen ions ($H^+$) when dissolved in water, have a sour taste, and turn blue litmus paper red.

Alkali

A base that is soluble in water and produces hydroxide ions ($OH^-$) when dissolved; they have a bitter taste, soapy feel, and turn red litmus paper blue.

Indicator

A chemical, such as litmus paper, that turns a different color depending on whether it is added to an acid or an alkali.

pH Scale

A scale from 1 to 14 used to measure the strength of an acid or alkali, where 1 is a strong acid, 7 is neutral, and 14 is a strong alkali.

Relative Atomic Mass ($Ar$)

The weighted average of the masses of the isotopes of an element on a scale where a carbon-12 atom has a mass of exactly 12 units, measured in $g/mol$.

Relative Formula Mass ($Mr$)

The sum of the relative atomic masses multiplied by the number of atoms of each element present in a chemical formula.

Percentage Composition

The percent by mass of each element in a compound, calculated as $\frac{Ar \times 100\%}{Mr}$.

Mole

A number equal to the number of carbon atoms in exactly $12\,g$ of pure carbon-12, which is Avogadro's number ($6.02 \times 10^{23}$).

Mole Ratio

A comparison of the moles of substances in a balanced chemical equation using the stoichiometric coefficients.

Molar Volume

The volume occupied by one mole of a gas, which is $22.4\,dm^3$ at STP or $24\,dm^3$ at room condition.

Empirical Formula

The simplest ratio in which atoms combine to form a chemical compound.

Molecular Formula

The formula showing the actual numbers of atoms that combine to form a molecule, calculated using the multiplier $n = \frac{\text{Molar Mass of Compound}}{\text{Empirical Formula Mass}}$.

Alkanes

A family of hydrocarbons characterized by single carbon-carbon bonds and the general formula $C_nH_{2n+2}$; their names end in -ane.

Alkenes

A family of hydrocarbons containing double carbon-carbon bonds with the general formula $C_nH_{2n}$; their names end in -ene.

Alkynes

A category of hydrocarbons featuring triple carbon-carbon bonds with the general formula $C_nH_{2n-2}$.

Organic Prefixes (meth- to hex-)

Naming conventions based on the number of carbon atoms: meth- (1), eth- (2), prop- (3), but- (4), pent- (5), and hex- (6).

Alcohols

A family of organic compounds whose names end in the suffix -ol.

Carboxylic Acids

A family of organic compounds whose names end in the suffix -oic acid.