c4 chemical changes Flashcards
what is the reactivity of a metal
related to?
the tendency to form positive ions
why are carbon and hydrogen included in the reactivity series?
they give you information about how metals will react with them
what is the reactivity series ordered in?
how reactive the elements are when reacting with water and dilute acids
what is the reactivity series?
(very reactive)
1. potassium
2. sodium
3. lithium
4. calcium
(fairly reactive)
5. magnesium
6. carbon
7. zinc
8. iron
(not very reactive)
9. hydrogen
10. copper
what can be done to metals that are less reactive than carbon?
they can be extracted from their ores by reduction with carbon
what does it mean when a metal is more reactive than hydrogen?
it can also react with an acid
what can happen if a metal is more reactive than another metal?
it can displace it
what is the equation for a metal reacting with an acid?
metal + acid—> salt + hydrogen
what indicated the speed of a metal acid reaction?
the rate in which the hydrogen bubbles are given off
what is the equation for when a metal reacts with water?
metal + water—> metal hydroxide + water
which elements will react with water?
potassium, sodium, lithium and calcium
which elements will not react with water?
zinc, iron and copper
what does reduction involve in terms of oxygen?
the reduction of oxygen
what does oxidation involve in terms of oxygen?
gain of oxygen
how are some metals found?
in their pure state
how are most metals found?
in compounds which require a chemical reaction to separate them
why can some metals be reduced with carbon?
because carbon reacts with oxygen to form carbon dioxide
what is oxidation in terms of electrons?
loss of electrons
what is reduction in terms of electrons?
gain of electrons
what happens in an oxidation redox equation?
the element loses electrons to become positively charged ions
what happens in a reduction redox equation?
the ion gains electrons to become an atom
what happens in a displacement reaction?
one element is replaced by a more reactive element
what is the equation for metals reacting with oxygen?
metal + oxygen= metal oxide
what the formula for an acid?
H and non metal
what types of ions do acids form in an aqueous solution?
H+ ions
whats the formula for a base?
metal oxide or metal hydroxide
what can bases neutralise?
acids
what is formed when a base neutralises an acid?
salt + water
what is the formula for a salt?
metal non-metal
what are alkalis?
bases that are soluble in water
what ions do alkalis form in aqueous solutions?
OH- ions
what does the pH scale tell us?
the acidity or alkalinity of a solution
what are pHs of acids?
0-6
what is the pH of a neutral solution?
7
what are the pHs of alkali solutions?
8-14
what happens when an alkali and acid react, in terms of ions?
H+ ions from acid and OH- ions from alkali react to form WATER
what does the production of water in a reaction mean?
it is a neutralisation reaction
what does the reaction between a acid and metal carbonate form?
salt + water + carbon dioxide
