spec niche

define atom

the smallest particle of an element which can exist

define molecule

a group of atoms chemically bonded together

relative mass of electron

0.0005

relative mass of proton

1

relative mass of neutron

1

relative charges of the subatomic particles

• electron = -1

• neutron = 0

• proton = +1

ph of metal oxides

bases - alkaline

ph of non-metal oxides

acidic

where does the steps on the periodic table begin?

underneath boron

when do ionic compounds conduct electricity?

• when molten

• when in aqueous solution

weakly alkaline ph

8-10

what are alkalis a source of in solution

hydroxide ions

what are calcium hydroxides in terms of solubility?

slightly soluble

what is used for measuring temperature change in combustion, displacement, dissolving and neutralisation?

calorimetry

define catalyst

substance that increases the rate of a reaction but is chemically unchanged at the end of the reaction

how does a catalyst work?

provides an alternative reaction pathway with a lower activation energy

examples of reversible reactions (2)

dehydration of hydrated copper (11) sulphate

thermal decomposition ammonium chloride - forms NH3 and HCl and then reforms NH4Cl

define homologous series

group of compounds with the same general formula

define functional group

groups of atoms which determines its chemical properties

define crude oil

mixture of hydrocarbons

why can nitrous oxides form in car engines?

the temperatures are high enough for nitrogen and oxygen from the air to react

cracking temperature

600-700

cracking catalysts

silica, alumina

products of substitution reactions

haloalkane + hydrogen halide

alkene + bromine —>

dibromoalkane

how is an addition polymer formed?

joining up many monomers

how many chlorines does chloroethene have?

1

problems with disposal of addition polymers (2)

• they are inert so do not biodegrade in landfill

• they produce toxic gases when burned