Rate Law
Definition
The rate law is an equation that relates the reaction rate with concentrations or pressures of reactants and constant parameters.
Analogy
Think of rate law as a recipe for baking cookies. The recipe (rate law) tells you how much of each ingredient (reactants) you need and how they should be mixed together (concentrations) to get your desired cookies (products) in a certain amount of time (reaction rate).
Related terms
Rate Equation: This is the mathematical representation of a rate law, showing the relationship between reaction rate and concentration of reactants. It’s like specific instructions in our cookie recipe – e.g., “Mix 2 cups flour with 1 cup sugar”.
Rate-Determining Step: In multi-step reactions, this is slowest step that determines overall reaction speed. It’s like waiting for dough to chill in fridge – no matter how fast we mix ingredients, we can’t proceed until dough has chilled.
Integrated Rate Law: This formulates relation between concentration of reactants and time; it helps predict amounts at any given point during reaction. It’s like knowing exactly when our cookies will be perfectly baked based on oven temperature and initial dough amount.
"Rate Law" appears in:
Study guides (4)
Practice Questions (13)
- A reaction has a rate law of R = k [A][B]. With respect to A, what is the order of reaction?
- A reaction has a rate law of the following: R = k [A][B]. What is the overall order of reaction?
- The rate law for the following reaction is R = k[XY]^2. The initial rate of the reaction was found to be 0.16 mol/Ls when the initial concentration of XY is 0.40 mol/L. What is the value of the rate constant, k?
- The rate law for the following reaction is R = k[A]^2. The initial rate of the reaction is defined as 0.080 mol/Ls, whereas the initial concentration of X is 0.20 mol/L. What is the value of the rate constant, k, for this reaction?
- The following mechanism is executed: (Step 1: H2O2 + I^- → IO^- + H2O) (Step 2: H2O2 + IO^- → H2O + O2 + I^-). Which statement is true about the overall reaction and rate law?
- The reaction described [O3(g) + O(g) → 2O2(g)] is the decomposition of O3. With an addition of NO, the reaction proceeds in two elementary steps and a mechanism is shown: [Step 1: O3 + NO → NO2 + O2 (slow)] [Step 2: NO2 + O → NO + O2 (fast)]. Which is the rate law?
- A mechanism is shown: [Step 1: 2NO2(g) → NO3(g) + NO(g) (slow)] [Step 2: NO3(g) + CO(g) → NO2(g) + CO2(g) (fast)]. Which is the correct rate law?
- What is the rate law for the following reaction: 2NO2(g) → NO(g) + NO3(g)
- What is the type of elementary step and rate law for A + 2B → C?
- Rate law is used to figure out ________________________.
- The entire rate law is based on which of the following?
- In most cases, the rate-determining step rate law isn't the rate law for the entire equation. Which of the following is an exception?
- A mechanism is shown below: [Step 2: 2X(g) ⇄ X2(g) (fast)] [X2(g) + Y(g) → X2Y(g) (slow)] The rate law is consistent with the one of the hypothetical reaction 2X(g) + Y(g) → X2Y(g). Which of the following is consistent with this mechanism?
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