Classes of Matter Practice Flashcards

Element

A pure substance which cannot be split into two or more simpler substances by any physical or chemical means; the simplest form of matter, with more than 114 known at present.

Metals

Elements that have lustre or shine, are good conductors of heat and electricity, and are malleable and ductile in the solid state; examples include sodium, zinc, copper, gold, iron, and aluminium.

Nonmetals

Elements that usually lack lustre, are bad conductors of heat and electricity, and are generally gases or soft and brittle solids; bromine is the only liquid example.

Metalloids

Elements with properties intermediate between those of metals and nonmetals; examples include boron, silicon, arsenic, antimony, bismuth, and germanium.

Compound

A pure substance formed from two or more elements combined together in a definite proportion by weight; its properties differ entirely from its constituent elements.

Mixture

A material containing two or more elements or compounds that are in close contact and mixed together in any proportion, where components retain their individual identities.

Homogeneous Mixture

A mixture with a uniform composition throughout its mass and no visible boundaries between constituents, such as air or a sugar solution.

Heterogeneous Mixture

A mixture that does not have a uniform composition throughout and has visible sharp boundaries between constituents, such as a mixture of sand and common salt.

Sedimentation

The process in which solid particles in a mixture of a liquid and an insoluble solid are allowed to settle at the bottom of the container.

Decantation

The process of separating a liquid from the sediment by carefully pouring the liquid into another container.

Centrifugation

A process used to separate suspended particles by rotating the mixture rapidly in centrifuge tubes, commonly used to separate cream from milk.

Residue

The solid particles blocked and collected on the filter paper during the process of filtration.

Filtrate

The liquid that passes through the fine pores of a filter paper during filtration and is collected in a beaker.

Sublimation

A separation method used when one component of a mixture vaporizes without melting and directly changes back into a solid upon cooling; used for ammonium chloride or iodine.

Crystallization

The process by which a pure solid in the form of crystals separates from a saturated solution; used to purify solids like potash alum or copper sulphate.

Distillation

A process where a liquid is heated to boiling and the produced vapours are condensed back into liquid; used to separate two miscible liquids with boiling points differing by at least $25^{\circ}\text{C}$.

Fractional Distillation

A method used to separate the components of a mixture of miscible liquids whose boiling points differ by $25^{\circ}\text{C}$ or less, such as methyl alcohol and acetone.

Chromatography

A technique used to separate solutes of a mixture that are soluble in the same solvent, originally used to separate coloured components of dyes.

Physical Change

A temporary change where physical properties are altered but the actual composition remains unchanged and no new substances are produced; examples include freezing of water or dissolving salt in water.

Chemical Change

A permanent change where substances are transformed into new substances with entirely different properties; examples include burning of wood, rusting of iron, or digestion of food.

Solute

The substance that is dissolved in a solvent to produce a solution; usually present in a lesser amount.

Solvent

The dissolving agent or medium of dispersion in a solution; water is the most common example.

Aqueous Solution

A solution produced by dissolving a substance in water.

Unsaturated Solution

A solution in which more solute can be dissolved at a given temperature.

Saturated Solution

A solution in which the maximum possible amount of a solute is dissolved at a given temperature.

Supersaturated Solution

A very unstable solution containing an amount of solute higher than that required for a saturated solution at a given temperature.

Solubility

The amount in grams of a solute dissolved in $100\,\text{g}$ of a solvent to make a saturated solution at a specific temperature and pressure; calculated as $\frac{\text{mass of solute}}{\text{mass of solvent}} \times 100$.

Suspension

A heterogeneous mixture in which small solid particles of diameter $10^{-5}\,\text{cm}$ or larger remain suspended throughout the mass of a liquid or gas.

Colloid

A heterogeneous mixture with properties intermediate between true solutions and suspensions, with particle sizes ranging from $10^{-7}\,\text{cm}$ to $10^{-5}\,\text{cm}$; examples include milk and ink.

Brownian Movement

The constant and rapid zigzag motion of colloidal particles caused by collisions with solvent particles.

Tyndall Effect

The scattering of a beam of light by colloidal particles, making the path of light visible.