ib chapter 1 chem vocab

element

chemical substance that can not be broken down by chemical means and a pure substance in which each atom has the same number of protons in the nucleus

elements in a compound

chemically combined compounds that can only be converted into their elements again by chemical reactions.

chemical properties

how a substance behaves in a chemical reaction.

physical properties

all the other properties of a substance
EX: melting point, density, hardness and electrical conductivity.

compound

pure substance formed when two or more elements combine chemically (can be split into separate elements)

mixture

components are not chemically bonded together, retaining their individual properties and can be mixed together in any proportion

homogeneous mixture

has the same composition throughout the mixture - consists of only one phase.

Ex: Solution/mixtures of gases

heterogeneous mixture

does not have uniform composition - consists of separate phases.

distillation

used to separate the solute (solid) and solvent from a solution or to separate a mixture of two liquids with different boiling points.

chromatography

used to test the purity of the product of a reaction. The presence of more than one spot indicates that the substance is impure.

kelvin

SI unit of temperature

absolute zero

the lowest temperature possible, corresponds to 0K or -273. °C (1°C = 1 K)

°C into K

add 273

K into °C

subtract 273

Temperature

A measure of the average kinetic energy (Ek) of the particles in a substance.

The higher the temperature, the higher the average kinetic energy of the particles.

Substance

Solid temp. below melting point
liquid temp. between melting and boiling point
gas temp. above boiling point

state symbols

(s) = solid
(I)= liquid
(g) = gas
(aq) = aqueous (dissolved in water)

endothermic

Changes of state which involve breaking forces of attraction between particles - requires heat

exothermic

Changes of state which involve forming forces of attraction between particles - heat energy is released when these forces are formed.

Solution

A homogeneous mixture of two or more substances - clear

Colloid

mixture whose particles never settle - not clear

Tendall effect

Scattering of a light beam as it passes through a colloid

Filtration

Separates solids from liquids

Evaporation

Separates solutes from solvent

Rf factor

distance travelled by component/distance travelled by solvent (chromatography)
DON'T leave as fraction!!!

Melting

solid to liquid

Vaporization

Liquid to gas

Condensation

Gas to liquid

Freezing

liquid to solid

Sublimation

solid to gas

deposition

gas to solid

Maxwell-Boltzmann distribution

At higher temperature = fewer particles with lower kinetic energy and more particles with higher kinetic energy the average kinetic energy of the particles is greater.

Solid

Particles are close together
Arrangement is regular
Shape is fixed
Vibrates
Moves slowest
Energy lowest
Force of attraction strongest

Liquid

Particles close (further than solids)
Arrangement random
Shape not fixed (takes shape)
Volume is fixed
Movement = moved around each other
Speed middle
Energy middle
Force of attraction middle (weaker than solid)

Gases

Particles far apart
Arrangement random
Shape not fixed (fills shape)
Volume is not fixed
Movement = moved around in all directions
Speed fastest
Energy highest
Force of attraction weakest