It may be different for your area. In my area the garage ceilings and walls which join living area have to be 5/8". All others areas 1/2" is fine. In addition as a kitchen is a fire risk area there may be requirements for fire proof lining to be used as well as water proofed - contact you local building control (Local Government) tye will be happy to advise
Yes there is. Different in many places. Consult local regulations wherever you are.
That is the thickness of the studs, -the inside of the wall.
You use 1/2 inch for ceilings
Partly the extra thickness, and partly a chemical they put in the mixture.
1/2 inch is the standard.
Fire retardant drywall should used when you finish off an attached garage as well as using a steel door on "passage" areas.
dung, drywall
Usually 5/8" .
24 + 24 for the ceiling.
No drywall is not a good shock absorber. It's too rigid.
For interior walls you want to use 1/2 inch size drywall. You want to use the thicker drywall because its stronger and it's a lot harder to damage than the thinner drywall.
The difference is the thickness and the type of paper covering the gypsum.