when the concentration of CHBr3 and NaOH are both .145, the rate of the reaction is .0040 M/s. What is the rate of the eaction if the concentration of CHBr3 is doubled?if the conc. is halved?if the two conc. are both increased by a factor of five?
CH3Br+NaOH-->CH3OH+NaBr
To determine how changes in concentration affect the rate of a reaction, we can use the rate law. The rate law describes the relationship between the concentration of reactants and the rate of the reaction.
The rate law for the given reaction can be written as:
rate = k[CHBr3][NaOH]
Where:
- [CHBr3] represents the concentration of CHBr3
- [NaOH] represents the concentration of NaOH
- k is the rate constant
Given that the rate of the reaction is 0.0040 M/s when [CHBr3] = [NaOH] = 0.145 M, we can substitute these values into the rate law to find the value of the rate constant (k).
0.0040 = k(0.145)(0.145)
k = 0.0040 / (0.145)(0.145)
k ≈ 0.182 M^(-2) s^(-1)
Now, let's analyze the effects of concentration changes on the rate of the reaction:
1. Doubling the concentration of CHBr3:
If the concentration of CHBr3 is doubled, [CHBr3] becomes 2 * 0.145 = 0.29 M. Since the concentration of NaOH remains the same, we can substitute these new values into the rate law:
rate = (0.182 M^(-2) s^(-1))(0.29 M)(0.145 M)
rate ≈ 0.0084 M/s
2. Halving the concentration of CHBr3:
If the concentration of CHBr3 is halved, [CHBr3] becomes 0.145 / 2 = 0.0725 M. We keep the concentration of NaOH the same:
rate = (0.182 M^(-2) s^(-1))(0.0725 M)(0.145 M)
rate ≈ 0.0018 M/s
3. Increasing both concentrations by a factor of five:
If both the concentration of CHBr3 and NaOH are increased by a factor of five, [CHBr3] and [NaOH] become 5 * 0.145 = 0.725 M. We substitute these new values into the rate law:
rate = (0.182 M^(-2) s^(-1))(0.725 M)(0.725 M)
rate ≈ 0.0948 M/s
So, the rate of the reaction will be approximately:
- 0.0084 M/s if the concentration of CHBr3 is doubled
- 0.0018 M/s if the concentration of CHBr3 is halved
- 0.0948 M/s if both concentrations of CHBr3 and NaOH are increased by a factor of five.