Question

Which unit can be used to express the rate of a reaction?

mL / s
mL / g
g / mL
mL / mol
s / mL

Answer 1

Answer: mL / s

Step-by-step explanation:

1) The rate of reaction is a speed. It is defined as the change in amount per time unit.

2) In form of equation reaction rate = Δ amount / time

3) Usually, it is more interesting to express the reaction rate in terms of the change of concentration, which is

reaction rate = Δ concentration / time

In those cases, the concentration is expressed in molar units per liter, so the rate is expressed as:

M / s = [mole/liter] / s

Which is what we usually find, but it is not mandatory.

4) So, other units can be used, like moles or volume (even pressure) to express the amount of a spices.

5) That is why rate of reation can be expressed as mL / s (mililiters per second).

Answer 2

The rate of reaction may be expressed as a unit of quantity divided by a unit of time. The only expression that has a quantity divided by time is the first one mL / s (i.e. milliliter per second), so the answer is the first option, mL/s.