Chapter 1–8 Lecture: Solutions, Concentrations, and Kinetics (Vocabulary Flashcards)

Vocabulary flashcards covering key terms and concepts from the lecture notes on solutions, concentrations, and reaction kinetics.

Percent concentration (w/v, w/w, v/v)

Ways to express how much solute is present in a solution: weight/volume (w/v), weight/weight (w/w), or volume/volume (v/v). A percent is a ratio out of 100, e.g., grams of solute per 100 mL or per 100 g of solution.

Mass to volume percent (m/v)

A percent expressing grams of solute per 100 milliliters of solution (e.g., 5 g NaOCl per 100 mL solution).

Weight to volume percent (w/v)

Same as mass to volume percent; often used interchangeably in lab contexts to express concentration.

Tonicity

The effective osmotic pressure of a solution relative to body fluids; influences fluid movement across membranes. Normal saline has a tonicity close to body fluids.

Normal saline

0.9% w/v sodium chloride solution used intravenously; isotonic with body fluids and considered an essential drug by WHO.

Isotonic / tonicity (0.9% NaCl in water)

A solution with the same effective osmotic pressure as body fluids, minimizing fluid shifts across cell membranes.

Molarity (M)

A unit of concentration equal to moles of solute per liter of solution.

Molar mass

The mass per mole of a substance, expressed in grams per mole (g/mol); used to convert grams to moles.

154 millimolar (154 mM)

A common molarity value derived from 0.9% NaCl in water, approximately 0.154 moles per liter.

Deciliter (dL)

A metric unit equal to 0.1 liter; convenient in medical lab contexts (e.g., mg/dL, g/dL).

100 mL = 0.1 L

A volume equivalence used to convert percent concentrations to molarity or other units.

Δ (delta)

Represents a change in a quantity, e.g., Δ[A] is the change in concentration of species A over a time interval.

Rate of reaction

The speed at which reactants are consumed or products are formed, typically expressed as Δconcentration/Δtime.

Negative sign in rate for reactants

Indicates consumption of a reactant; for products, rates are positive (production). Conventionally, -d[A]/dt is used for reactants.

Stoichiometric coefficients (a, b, c)

Small integers in a balanced equation A + B → C that relate how much of each species reacts or is produced.

Relative rate expression

A rate relationship derived from stoichiometry that relates the rate of change of one species to another via the reciprocals of their coefficients.

One-to-one stoichiometry

When coefficients are 1:1, the rates of appearance/disappearance are equal for the involved species.

Method of initial rates

Kinetics approach focusing on the rate measurements at the very start of a reaction, when concentrations are close to initial values.

Hydrogen peroxide decomposition (balanced equation)

2 H2O2 → 2 H2O + O2; rate relations: -d[H2O2]/dt = d[H2O]/dt = 2 d[O2]/dt (equivalently, -1/2 d[H2O2]/dt = d[H2O]/dt = 1/2 d[O2]/dt).

Concentration vs. time graph in kinetics

A graph showing how reactant/product concentrations change over time; the slope represents the rate (steep initially, then flattens as reactants are consumed).