Acids Reacting With Metals (T2)

Question 0

What substance must be present for a substance to be acidic?

Answer 0

Hydrogen

Question 1

Generally all acids react with metals in a similar way. Explain this using “iron + sulphuric acid” and “iron + hydrochloric acid”..

Answer 1

Iron + sulphuric acid -> iron sulphate + hydrogen
Fe(s) + H2SO4(aq) -> FeSO4(aq) + H2(g)

Iron + hydrochloric acid -> iron (II) chloride + hydrogen
Fe(s) + 2HCl(aq) -> FeCl(aq) + H2(g)

In both of the above equations a ‘displacement reaction’ is occurring.

The hydrogen is being liberated from the acid and the other molecules are then bonding with the metal involved.

This is called ‘forming a salt’

Question 2

When exposing different …… to ……. , the most reactive will react …….. or very …….. , often with the most …….. or …….. reaction. The ……. reactive will react much more …….. and in a much less ……… manner.

Answer 2

When exposing different elements to acids, the most reactive will react immediately or very quickly, often with the most violent or energetic reaction. The least reactive will react much more slowly and in a much less energetic manner.

Question 3

In acids, hydrogen is the most important part of the molecule, so what will happen to anything that is more reactive than it?

Answer 3

Anything more reactive that hydrogen will displace it.

Question 4

In acids, if an element is less reactive that hydrogen, eg: copper (Cu) what will happen?

Answer 4

It will not interact with the hydrogen

Question 5

What happens when magnesium reacts with hydrochloric acid?

Answer 5

• liquid will effervesce
• hydrogen gas will be given off
• reaction will be exothermic

Mg(s) + 2H+(aq) + 2Cl-(aq) -> Mg2+(aq) + 2Cl-(aq) + H2(g)

• HCl splits up in water which is why they are down as separate ions
• the electrons are taken from the magnesium by the hydrogen ions while the chlorine ions remain unchanged

Question 6

What happens when magnesium reacts with sulphuric acid?

Answer 6

• liquid will effervesce
• hydrogen gas will be given off
• reaction will be exothermic

Mg(s) + 2H+(aq) + SO4 2-(aq) -> Mg2+(aq) + SO4 2-(aq) + H2(g)

• the electrons are taken from the magnesium by the hydrogen ions while the sulphate ions remain unchanged

Question 7

What happens when aluminium reacts with HCl?

Answer 7

• slower to react than magnesium as it is further down the reactivity series, but it reacts in a similar way
• needs to be heated (Mg reacts at room temperature)

2Al(s) + 6HCl(aq) -> 2AlCl3(aq) + 3H2(g)