Section 1 Flashcards

Particles are arranged in a regular, tightly packed lattice structure and vibrate about fixed positions.

Particles are closely packed but arranged randomly, and they can slide past one another and flow.

Particles are widely spaced, arranged randomly, and move rapidly in all directions at high speeds.

Because the thermal energy supplied is used to overcome and break the forces holding the particles together, rather than increasing their kinetic energy.

The net movement of particles from an area of higher concentration to an area of lower concentration down a concentration gradient, due to their random motion.

Ammonia has a lower relative molecular mass (\(M_{\text{r}} = 17\)) than hydrogen chloride (\(M_{\text{r}} = 36.5\)), so ammonia gas diffuses faster and travels further in the same time.

The maximum mass of solute in grams that can dissolve in 100 grams of solvent at a specific temperature.

A solution containing the maximum mass of dissolved solute at a specific temperature, where no more solute can dissolve.

Element: a substance made of only one type of atom. Compound: two or more elements chemically combined in fixed proportions. Mixture: two or more substances not chemically combined.

Proton: mass = 1, charge = +1. Neutron: mass = 1, charge = 0. Electron: mass = 1/1836 (approx. 0), charge = -1.

Atomic number: the number of protons in the nucleus of an atom. Mass number: the total number of protons and neutrons in the nucleus.

Atoms of the same element with the same number of protons but different numbers of neutrons.

The weighted average mass of an atom of an element compared with 1/12th of the mass of a carbon-12 atom.

\(A_{\text{r}} = \frac{(\text{mass}_1 \times \%_1) + (\text{mass}_2 \times \%_2)}{100}\).

In order of increasing atomic (proton) number. Elements in the same group have the same number of outer-shell electrons.

\(\text{Moles} = \frac{\text{Mass (g)}}{M_{\text{r}}\text{ (or } A_{\text{r}}\text{)}}\).

Empirical formula: the simplest whole-number ratio of atoms of each element in a compound. Molecular formula: the actual number of atoms of each element in a molecule.

Percentage yield = (Actual yield / Theoretical yield) ×100.

Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. One mole of any gas occupies 24 dm³ (24000 cm³) at room temperature and pressure (RTP).

Moles=Concentration (mol/dm³) × Volume (dm³). (Volume in dm³ = volume in cm³ / 1000).

By the electrostatic attraction between oppositely charged ions, formed by the transfer of electrons from a metal to a non-metal.

They have a giant ionic lattice held together by strong electrostatic attractions between oppositely charged ions, requiring large amounts of energy to overcome.

By the electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.

Simple molecular substances have weak intermolecular forces between molecules that require little energy to break. Giant covalent substances contain many strong covalent bonds throughout a giant lattice that require massive energy to break.

Malleable because the layers of metal ions can slide over one another without breaking the metallic bond. Conduct electricity because they contain a sea of delocalised electrons that are free to move and carry charge.

The decomposition of an electrolyte by passing an electric current through it.

Cathode (negative): hydrogen gas is formed unless the metal ion is less reactive than hydrogen (e.g. copper). Anode (positive): oxygen gas is formed unless halide ions (Cl⁻, Br⁻, I⁻) are present at high concentration, in which case the halogen is formed.