C5: chemical changes Flashcards
what does reactivity mean
how vigorously a substance chemically reacts
how can metals be ordered by their reactivity
by comparing their reactions with water, acid, or oxygen
what name is given to a list of metals ordered by their reactivity
reactivity series
in terms of electrons, what makes some metals more reactive than others
they lose their outer shell electrons more easily
why are gold and silver found naturally as elements in the earth’s crust
they are very unreactive
what is an ore
rock containing enough of a metal compound to be economically worth extracting
how are metals less reactive than carbon extracted from their ores
reduction with carbon
in terms of oxygen, what is oxidation
addition of oxygen
in terms of oxygen what is reduction
removal of oxygen
why can metals like potassium and aluminium not be extracted by reduction with carbon
because they are more reactive than carbon
how are metals more reactive than carbon extracted from their ores
electrolysis
what is a displacement reaction
a more reactive substance takes the place of a less reactive substance in a compound
what is an ionic equation
equation which gives some substances as ions and has spectator ions removed
what type of substance is given as ions in an ionic equation
ionic compounds in solution
what is a spectator ion
ion that is unchanged in a reaction
what is a half equation
equation that shows whether a substance is losing or gaining electrons
in terms of electrons what is oxidation
loss of electrons
in terms of electrons what is reduction
gain of electrons
in terms of pH what is an acid
a solution with a pH of less than 7
in terms of pH what is a neutral solution
a solution with a pH of 7
in terms of H+ ions what is an acid
a substance that releases H+ ions when dissolved in water
how is the amount of H+ ions in a solution related to it’s pH
the more H+ ions, the lower the pH
what are the names and formulae of three main acids
hydrochloric acid,HCl, sulfuric acid,H₂SO₄, nitric acid, HNO₃
how do you measure the pH of a substance
universal indicator or pH probe
what is a strong acid
an acid where the molecules or ions completely ionise in water
what is a weak acid
an acid where the molecules or ions partially ionise in water
what is a salt
compound formed when a metal ion takes the place of a hydrogen ion in an acid
which type of salts fo sulfuric acid, hydrochloric acid and nitric acid acid form
sulfates,chlorides,nitrates
what are the products of a reaction between a metal and an acid
salt + hydrogen
what are the products of a reaction between a metal hydroxide and an acid
salt + water
what are the products of a reaction between a metal oxide and an acid
salt + water
what are the products of a reaction between a metal carbonate and an acid
salt + water + carbon dioxide
what is a base
substance that reacts with acids in neutralisation reactions
what is an alkali
substance that dissolves in water to form a solution above pH 7
what is a neutralisation reaction
a reaction between an acid and a base to produce water
what is the ionic equation for a reaction between an acid and an alkali
H⁺(aq) + OH⁻(aq) → H₂O(l)
how do you obtain a solid salt from a solution
crystallisation
when an acid reacts with a metal, which species is oxidised
the metal
when an acid reacts with a metal which species is oxidised
hydrogen
what are the four state symbols and what do they stand for
(s) solid, (l) liquid, (g) gas, (aq) aqueous or dissolved in water
what is the formula for sulfate
SO4 2-
What is the formula for nitrate
NO3
what is the formula for carbonate
CO3 2-
what is the formula for hydrochloric
HCl
