why do some explosive mixtures oxidise faster than others?

Question

Or how are oxidation reactions used to cause explosions?

in terms of oxidation reactions and oxidisers

Answer 1

If you think in terms of reactant(s) going to product then a single compound (like nitoglycerine) will usually react faster than a mixture (like gun powder).

The biggest single issue seems to the the heat of the reaction. The more heat generated per mole, the greater the explosion.

Another factor is the number of moles of gas (or liquids which are vaporized during the reaction) that are generated when the compound or mixture explodes. The larger the amount of gases the greater the pressure or final volume.