What are the units usually used to express the rates of reactions occuring in a solution?

Answer 1

Rates are complicated.

Suppose you have:

A ---> B

The rate would the simple be:

Rate = -[A]/s = [B]/s

or the dissapearance of the concentration of A per sec or the appearance of the concentration of B per second.

You see how complicated it can become if you have a reaction like this:

A + 2 B + 5 C + 12 D --> E + 2 F + 4 G + 7 H

here you'd have to find out what the limiting reagent is and then measure it's rate of change/time. The Rate equation for this reaction is:

Rate = [E][F]^2[G]^4[H]^7/
([A][B]^2[C]^5[D]^12)

no clue what the units to that would be!

Answer 2

Reaction rates are measured in terms of the change in concentration per unit time.
The unit is Molarity per second (M / s), or moles per Liter per second.

Even when you have a very complicated reaction, the unit of the reaction rate is still Molarity per second. It is the rate constant (k) which has units which will vary from reaction to reaction in order to keep the final unit of the answer the same.

Answer 3

it depends on what order the reaction is, you have to determine the overall reaction. its in units of t in seconds. there is a general formula:
units of k=((L/mol)^order-1)/unit of t...

mol/L*s- 1st order rxn...or( mol L ^-1 s^-1)

1/s- 1st order..or (s^-1)

L/mol*s- 2nd order,or (L mol ^-1s^-1)

L^2/mol^2*s- 3rd order...or (L^2 mol^-2 s^-1)

fyi-the * is multiply, ^ is raised to that power, its hard to put in comp. rates are tricky ,hope this helps

Answer 4

Seconds?? haha not there yet in chem..just an idea..