Introduction to Quantitative Chemistry - VOCABULARY Flashcards

A set of 100 vocabulary-style flashcards covering key concepts from the lecture notes on chemical reactions, stoichiometry, the mole concept, solutions, and gas laws.

Chemical reaction

A process where reactants are transformed into products via bond breaking and formation.

Reactants

Substances that are consumed in a chemical reaction.

Products

Substances formed as a result of a reaction.

Bond breaking

The process of breaking chemical bonds in reactants during a reaction.

Bond forming

The creation of new bonds to form products.

Conservation of Mass

The total mass of reactants equals the total mass of products in a closed system.

Conservation of Charge

The total electric charge is balanced on both sides of a chemical equation.

Atoms conserved

The number of each type of atom remains the same on both sides of a reaction.

Balanced equation

An equation with equal numbers of each element on both sides.

Coefficients

Numbers placed before chemical formulas to indicate relative amounts.

Relative amounts (stoichiometric ratios)

Proportions of reactants and products given by coefficients.

Linking equations to moles

Using coefficients to relate moles of substances in a reaction.

Mole

A unit equal to 6.022×10^23 particles.

Avogadro's number

The number of particles in one mole, 6.022×10^23.

6.022 × 10^23

Numerical value of Avogadro's number.

Atomic mass unit (amu)

1/12 the mass of a carbon-12 atom; a relative unit.

Relative formula mass

Sum of the relative atomic masses of atoms in a formula (g/mol).

Molar mass

Mass of one mole of a substance (g/mol).

Molar mass (definition)

The mass, in g/mol, of one mole of a substance.

n = m/MM

Moles = mass divided by molar mass.

n = N/Na

Moles = number of particles divided by Avogadro's number.

Na (Avogadro's number)

Constant 6.022×10^23 used to convert between particles and moles.

MM (molar mass)

Molar mass; the g/mol value used to convert mass to moles.

Empirical formula

The simplest whole-number ratio of elements in a compound.

Molecular formula

The actual number of each type of atom in a molecule.

Empirical formula derivation

Process to determine the simplest ratio from experimental data.

Percentage composition

Mass percentage of each element in a compound.

Empirical vs molecular relationship

Molecular formula may be a multiple of the empirical formula.

MgO experiment

Experiment to determine the empirical formula of magnesium oxide by heating Mg.

Limiting reagent

The reactant that is consumed first, limiting product formed.

Excess reagent

Reactant left over after the reaction completes.

Theoretical yield

Maximum amount of product predicted by stoichiometry.

Experimental yield

Actual amount of product obtained in an experiment.

Percent yield

(Experimental yield / Theoretical yield) × 100%.

Mass percentage formula

(mass of element in compound / mass of compound) × 100%.

Mole concept

A counting unit used to bridge macroscopic mass and microscopic particles.

Simple whole-number ratios

Basic stoichiometric ratios of reactants/products in a balanced equation.

n = number of moles

Symbol n represents the amount in moles.

Percent composition calculation

Procedure to compute element percentages in a compound.

Solubility

Maximum amount of solute that can dissolve in a solvent at a given temperature.

Saturated solution

A solution containing the maximum dissolved solute at a given temperature.

Unsaturated solution

A solution that can still dissolve more solute at the given temperature.

Solubility and temperature

Solubility often increases with temperature for many solids.

Dynamic equilibrium

Forward and reverse dissolution/precipitation occur at equal rates.

Precipitation

Formation of a solid from a solution when solubility is exceeded.

Saturation point

Concentration at which no more solute can dissolve at a given temperature.

Dissolution

The process of a solute dissolving in a solvent.

Solvation

Interaction of solute with solvent molecules (hydration in water).

Aqueous solution

Solution where the solvent is water.

Dissociation

Ions separate into constituent ions in solution (electrolytes).

Dissolution vs precipitation

Dynamic balance between solute dissolving and solid forming.

Concentration

Amount of solute per given amount of solvent/solution.

Molarity

Moles of solute per liter of solution.

c = n/V

Molarity formula: concentration equals moles divided by volume.

Dilution

Reducing concentration by adding solvent; moles before equal moles after.

n1 = n2

Conservation of moles during dilution.

Standard solution

A solution of known concentration used for calibration.

Making solutions

Process to prepare solutions with desired concentrations.

Solvent

Substance present in largest amount that dissolves the solute.

Solute

Substance dissolved in the solvent.

Solute-solvent interactions

Forces between solute and solvent driving dissolution.

Apparatus: Measuring cylinder

Glassware for rough volume measurements.

Pipette

Glassware for transferring precise volumes.

Burette

Glassware used for precise volume delivery (titrations).

Volumetric flask

Glassware for preparing solutions with accurate volumes.

% (w/v)

Percent weight/volume concentration (g per 100 mL).

% (v/v)

Percent volume/volume concentration (mL per 100 mL).

% (w/w)

Percent weight/weight concentration (g per 100 g).

ppm

Parts per million; mass of solute per mass of solution.

mg/kg

Milligrams of solute per kilogram of solution.

Barometer

Instrument that measures atmospheric pressure using a mercury column.

Density of Hg

13,600 kg/m^3; used to convert height to pressure in barometry.

Atmospheric pressure

Pressure exerted by the atmosphere; ~101.3 kPa at sea level.

1 atm

Standard atmospheric pressure (101.3 kPa).

Pascal (Pa)

SI unit of pressure (N/m^2).

Kilopascal (kPa)

1000 Pa.

Gases

Substances in the gaseous state with constant random motion.

Pressure

Force per unit area exerted by a gas on container walls.

Temperature

Measure of average kinetic energy of gas particles.

Volume

Space occupied by a gas.

P ∝ T

Pressure increases with temperature when n and V are fixed.

P ∝ 1/V

Pressure increases as volume decreases when n and T are fixed.

Kinetic Theory of Gases

Model describing gas behavior with postulates.

Postulate: empty space

Gases occupy mostly empty space between molecules.

Postulate: straight-line motion

Gas particles move in straight lines with random directions.

Postulate: elastic collisions

Collisions conserve kinetic energy.

Postulate: no attraction

Gas particles exert no intermolecular attraction.

PV = nRT

Ideal gas equation relating pressure, volume, moles, temperature and R.

R value 8.314

Gas constant in SI units used in PV = nRT.

STP molar volume

Volume occupied by 1 mole of an ideal gas at STP (≈22.71 L at 0°C).

Real gas

Gas that deviates from ideal behavior at high pressure or low temperature.

Ideal gas

Gas that perfectly follows PV = nRT under appropriate conditions.

PV/RT ≈ 1

Indicator that a gas behaves ideally under chosen conditions.

Combined Gas Law

P1V1/T1 = P2V2/T2 for a fixed amount of gas.

Avogadro’s Law

Equal volumes of gases at same T and P contain the same number of molecules.

Boyle’s Law

For fixed n and T, P ∝ 1/V.

Charles’ Law

For fixed n and P, V ∝ T.

Absolute zero

0 K; theoretically no molecular motion.

Partial pressure

Pressure contributed by a single gas in a mixture.

Total pressure

Sum of the partial pressures of all gases in a mixture.