Question

What would decrease the rate of most chemical reactions?
a. increasing the concentration of reactant atoms
b. increasing the size of the reactant particles
c. adding an appropriate catalyst
d. all of the above

Answer 1

The answer is B

Increasing the concentration of your reactant atoms will put them in closer proximity and allow them to come into contact quicker.

Increasing the size of the reactant particles will decrease the surface area the reactant atoms have to interact with each other. For instance, if you're trying to burn 100g of wood in the form of a large block, and 100g of word in the form of sawdust, the sawdust is going to burn much faster because it has a much larger total surface area than a block of wood has.

Adding an appropriate catalyst will lower the activation energy of the reaction and allow it to proceed much faster.