Ionic Equation problem - Prelim Chemistry Metals Topic (1 Viewer)

[Deadboxes]

Hi,


I'm having an issue writing out the ionic equation for:
Sulphuric Acid + Magnesium
H2SO4 + Mg -> MgSO4 + H2
I've rewritten it as:
H2 + Mg -> Mg + H2
But the answer section says:
2H + Mg -> Mg + H2

What have I done wrong?

Thanks, guys.

 

[jazz519]

The H2 in H2SO4 is not hydrogen gas, they are hydrogen ions and thus why the equation should be 2H^+(aq) + Mg(s) ---> Mg^2+(aq) + H2(g). Remember to include the ion charges and states of matter for the equations.

Another way you can do it is:
1) first break everything into the anions and cations so: 2H^+(aq) + SO4^2-(aq) + Mg(s) ----> Mg^2+(aq) + SO4^2-(aq) + H2(g) and then I assume you want the net ionic equation, so remove any spectator ions i.e. the so4^2- giving the same equation as in the first shown

 

[Deadboxes]

Ah I understand thank you!