The rate law for the reaction Cl2(g)+CHCl3(g) ⟶HCl(g)+CCl4(g) is Rate =k[Cl2]^1 / 2[CH Cl3] Wha

The rate law for the reaction Cl2(g)+CHCl3(g)...

The rate law for the reaction
$$
\mathrm{Cl}_{2}(g)+\mathrm{CHCl}_{3}(g) \longrightarrow \mathrm{HCl}(g)+\mathrm{CCl}_{4}(g)
$$
is
$$
\text { Rate }=k\left[\mathrm{Cl}_{2}\right]^{1 / 2}\left[\mathrm{CH} \mathrm{Cl}_{3}\right]
$$
What are the units for $k$ assuming time in sceonds?

Key Concepts

Rate Law

The rate law describes the relationship between the reaction rate and the concentration of the reactants, where each concentration is raised to a specific power (the reaction order). It provides insight into how changes in concentration affect the speed of the reaction.

Reaction Order

The reaction order is the sum of the exponents on the concentration terms in the rate law. It indicates the overall dependency of the reaction rate on the concentrations of the reactants, which in turn determines how the units of the rate constant must be adjusted to maintain dimensional consistency.

Rate Constant

The rate constant (k) is a proportionality factor in the rate law that quantifies the intrinsic speed of the reaction under given conditions. Its units depend on the overall order of the reaction. For a reaction that is nth-order overall, if the rate is expressed in concentration per time (e.g., M/s) and concentration in M, then the units of k are typically M^(1-n)/s.

Dimensional Analysis

Dimensional analysis is a mathematical tool used to check the consistency of units within an equation. In the context of chemical kinetics, it ensures that the derived units for the rate constant k are correct, by balancing the units of the rate (such as M/s) with the concentrations raised to their respective powers.

Transcript

00:01 So in this case, the actual reaction isn't necessary to solving the problem.

00:05 We're given the rate law, which is that rate equals k times the concentration of cl2 to the one -half power times the concentration of ch, cl3.

00:19 Now, this is really just going to end up being like a unit conversion or like a unit matching sort of problem.

00:26 But i'd like to make a note that this right here, this can definitely be troublesome to a lot of people learning.

00:32 Kinetics and the explanation is that like you know it's difficult to explain half of a reactant reacting you know in a collision but the reason we have this is because you know kinetics isn't a perfect science and a lot of this is you know part of it's just empirical in other words looking at data and seeing what fits and so sometimes you will see rate laws with one half or non integer orders and sometimes you'll even see negative orders and you just have to accept that and realize that that's part of, you know, what's been found experimentally.

01:07 You know, chemistry is an experimental science.

01:09 And so back to solving the problem.

01:11 The rate here, rate is always given to us in moles per liters per second.

01:19 That's just what a rate is.

01:21 Change in concentration.

01:23 That's that part, the moles per liters over time.

01:25 This is the seconds part.

01:27 The units of k were going to fill out.

01:29 So i'll leave an empty parentheses there.

01:32 The units of cl2 to the one -half power...