DGC Grade 11 Quantitative Chemistry - Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering polyatomic ions, the mole concept, solution concentration, stoichiometry, gas laws at STP, and common quantitative chemistry quantities and processes.

Ammonium ion

NH4+, a polyatomic cation formed when ammonia accepts a proton; common in ammonium salts.

Hydronium ion

H3O+, the hydrated proton; responsible for acidity in aqueous solutions.

Chlorate

ClO3−; polyatomic ion used in salts and oxidizing reactions.

Ethanoate

CH3COO− (acetate); conjugate base of ethanoic acid (acetic acid).

Hydroxide

OH−; polyatomic ion that makes solutions basic.

Nitrate

NO3−; polyatomic ion common in fertilizers and explosives.

Nitrite

NO2−; polyatomic ion used in preservation and disinfection; weaker oxidizer than nitrate.

Permanganate

MnO4−; strong oxidizing polyatomic ion.

Hydrogen carbonate

HCO3−; also called bicarbonate; acts as a buffer in biological systems.

Hydrogen sulphate

HSO4−; bisulfate; conjugate base of sulfuric acid.

Carbonate

CO3^2−; polyatomic ion in rocks and carbonated drinks.

Dichromate

Cr2O7^2−; polyatomic ion used in some cleaning agents and titrations.

Sulfate

SO4^2−; polyatomic ion common in salts (e.g., magnesium sulfate).

Sulphite

SO3^2−; polyatomic ion used in food and preservation; reducing agent.

Phosphate

PO4^3−; essential polyatomic ion in biology and agriculture.

Thiosulphate

S2O3^2−; polyatomic ion used in bleaching and photography.

Hypochlorite

ClO− (or OCl−); polyatomic ion used in bleaches and disinfection.

Avogadro's number

NA = 6.02 × 10^23 mol−1; number of particles in one mole of any substance.

Mole

The SI unit for amount of substance; amount containing NA particles (atoms, molecules or ions).

Relative atomic mass

The average mass of an atom relative to 1/12 the mass of a carbon-12 atom; used to determine molar masses.

Molar mass

M; mass in grams of one mole of a substance (g·mol−1).

n = m / M

Formula to calculate moles (n) from mass (m) and molar mass (M).

Molar concentration (Molarity)

c = n / V; number of moles of solute per liter of solution (mol·L−1).

Standard solution

A solution of known concentration used for calibration and experiments.

Molar volume (Vm)

22.4 dm^3 per mole at STP; volume occupied by one mole of gas.

STP (Standard Temperature and Pressure)

0°C (273 K) and 1 atm (101.3 kPa) used as standard conditions for gas calculations.

n = V / Vm

Mole calculation for gases where V is volume and Vm is molar volume.

Gas volume relation (V = nVm)

Volume of a gas equals number of moles times the molar volume (at a given T and P).

Balanced chemical equation

An equation with equal numbers of each type of atom on both sides and correct formulas, with states indicated (s, ℓ, g, aq).

Conservation of atoms

In a chemical reaction, atoms are conserved; the total number of each type of atom remains the same on both sides.

Conservation of mass

Mass is conserved in a chemical reaction; total mass of reactants equals total mass of products.

Mole ratio

The proportional relationship of reactants and products as given by the balanced equation (e.g., 2Mg:1O2 in 2Mg + O2 → 2MgO).

Limiting reagent

The reactant that is completely consumed first, limiting the amount of product formed.

Excess reagent

The reactant that remains after the limiting reagent is consumed.

Theoretical yield

Maximum amount of product that could be formed from the given amounts of reactants based on stoichiometry.

Actual yield

The amount of product actually obtained from a reaction.

Percentage yield

(Actual yield / Theoretical yield) × 100; measures efficiency of a reaction.

Percentage purity

(mass of reacting substance / total mass of impure sample) × 100; assesses sample purity.

Concentration formula (c = n / V)

Expression for molarity; n is moles of solute, V is volume of solution in dm^3.

Solute

Substance dissolved in a solvent.

Solvent

Substance in which another substance dissolves; the dissolving medium.

Volumetric flask

Laboratory glassware used to prepare solutions to a precise final volume.

Tare

Zeroing a balance before weighing to account for the mass of containers or boats.