How do chemist control the speed of explosions?

Explosives are chemicals that have very fast burn rates at different degree.

First the Dynamite:

-The dynamite is an explosive that made from nitroglycerin, and it is a type of the explosive that has a fast burning rate and makes it very strong explosive. Physical shock can make the dynamite to explode and makes it highly dangerous.

-But the fireworks are a class of low explosive, the stuff that used in it is black powder.Because this explosive has a slow burn rate than dynamite that makes it less dangerous and safer than dynamite explosives

-SO although the dynamite and the fireworks are both explosives they have different burn rates which make them totally different in safeness.

Explanation:

the answer is c.the valence of the atoms combine .