Question

For the reaction N₂(g) + O₂(g) --> 2NO(g), if the initial concentration of NO was 0.00M and the concentration of NO was 0.419 after 20 seconds, what is the average rate for the reaction over the first 20 seconds?

Answer 1

Average rate: It is rate of change of concentration of reactant or product divided by time taken.

For example let's take a look at this reaction

# X→Y

​​​​​​​​​​At time t1 concentration of X is [X1] and that of Y is [Y1]

thus at time t2 concentration of X will be [X2] and that of Y will be [Y2]

∆t = t2 - t1

∆[X] =[X]2 - [X]1

∆[Y ]= [Y]2 - [Y]1

thus,

Average rate = -∆[X]

______

∆t

*Negative sign represents concentration of reactant is decreasing*

*[X] square brackets represents molar concentration.

Similarly Average rate = ∆[Y]

______

∆t

Solution: