[Bobixtt]

Hi everyone!
I'm writing two reports and I got doubt, I know it may sound stupid, but my colleague confused me and I need clarification 

The two reactions I'm analyzing are:
1) dehydration of sugar with sulfuric acid
2) Reactions of lithium with air

In my opinion they are both chemical transformations, not just physical, in fact the first one is an elimination reaction and a second one is a combustion. Am I wrong? Thank you all for your help

[Borek]

In my opinion they are both chemical transformations, not just physical, in fact the first one is an elimination reaction and a second one is a combustion.

Sounds OK to me.

[AWK]

Lithium reacts with both oxygen and nitrogen in the air.

[umut]

2) Reactions of lithium with air

When lithium reacts with air, only combustion does not occur. We can talk about 2 reactions:
4Li + O2 → 2Li2O ( combustion reaction )
6Li +N2 → 2Li3N2 ( Synthesis reaction )

The rest of the post, you are right