How to Calculate Reaction Rate: Formula and Examples

📚 Quick Study Guide

• ⚛️ The reaction rate is the speed at which reactants are converted into products in a chemical reaction.
• ⏱️ It is typically expressed as the change in concentration of a reactant or product per unit time (e.g., mol/L·s).
• 📝 The general formula for reaction rate is: $Rate = -\frac{\Delta[Reactant]}{\Delta t} = \frac{\Delta[Product]}{\Delta t}$, where $\Delta$ represents 'change in'.
• 🌡️ Reaction rates are affected by factors such as temperature, concentration of reactants, surface area (for solids), and the presence of catalysts.
• ➕ A catalyst speeds up a reaction without being consumed in the process.
• 🧪 To determine the rate law experimentally, measure the initial rate of the reaction for different initial concentrations of reactants.
• 📈 Understanding reaction rates is crucial in many fields, including industrial chemistry, environmental science, and biochemistry.

Practice Quiz

1. Question 1: What is the correct formula for calculating the average rate of a reaction?
   1. A) $Rate = \frac{\Delta t}{\Delta[Reactant]}$
   2. B) $Rate = \Delta[Reactant] \times \Delta t$
   3. C) $Rate = -\frac{\Delta[Reactant]}{\Delta t}$
   4. D) $Rate = \frac{[Reactant]}{\Delta t}$
2. Question 2: If the concentration of a reactant decreases from 1.0 M to 0.5 M in 10 seconds, what is the average rate of the reaction?
   1. A) 0.025 M/s
   2. B) 0.05 M/s
   3. C) 0.1 M/s
   4. D) 0.2 M/s
3. Question 3: Which factor does NOT affect the rate of a chemical reaction?
   1. A) Temperature
   2. B) Concentration of reactants
   3. C) Presence of a catalyst
   4. D) Color of the reactants
4. Question 4: What is the role of a catalyst in a chemical reaction?
   1. A) To be consumed in the reaction
   2. B) To slow down the reaction
   3. C) To speed up the reaction
   4. D) To shift the equilibrium towards reactants
5. Question 5: In the reaction $A + 2B \rightarrow C$, if the rate of formation of C is 0.1 M/s, what is the rate of consumption of B?
   1. A) 0.05 M/s
   2. B) 0.1 M/s
   3. C) 0.2 M/s
   4. D) 0.4 M/s
6. Question 6: What is the typical unit for expressing the rate of a reaction?
   1. A) M·s
   2. B) $M/s^2$
   3. C) M/s
   4. D) $s/M$
7. Question 7: If the rate law for a reaction is $Rate = k[A]^2[B]$, what is the overall order of the reaction?
   1. A) 1
   2. B) 2
   3. C) 3
   4. D) 4