Question

Which one of the following is not a combination reaction?

A. HNO3 (aq) + KOH (aq) → H2O (l) + KNO3 (aq)
B. 2CaO + 3CO2 → 2CaCO3
C. Na2O + CO2 → Na2CO3
D. 4Fe + 3O2 → 2Fe2O3

Answer 1

What one of the reactions looks different to the other? Chemical equations that look similar usually have the same type of reaction and are laid out in the same way.

Remember what combination means, basically putting two things together to make one big thing, to COMBINE things together to make something else. What equation doesn't do that?

Answer 2

A

Answer 3

Yes! Well done :)