Kinetics: Reaction Rates Flashcards
1
Q
What is the definition of the rate of reaction?
A
- The change of concentration of reactant/product over time
- The measure of the amount of product formed or reactant used over time
- The units of rate of reaction may be given as g/s, cm3 / s or mol/s
2
Q
What factors will increase the rate of reaction?
A
- Increase in temperature
- Increase in concentration of reactants
- Increase in pressure of gaseous reactants
- Increase in surface area of solid reactants
- Adding a catalyst
3
Q
What is the effect of temperature on the rate of reaction?
A
- At higher temperatures, the particles are moving faster, so the collision frequency increases
- Increased movement of the molecules means collisions will occur more often and with greater energy
- Increased temperature increases rate of reaction
- Increases collision frequency
- Increases proportion of successful collisions
4
Q
What is the effect of concentration of reactants on the rate of reaction?
A
- When the concentration of a sample is increased, more molecules of substance occur in the same volume meaning they are packed closer together
- This increases collision frequency
- Increased concentration increases rate of reaction
- Increases collision frequency
- Speed of particles are the same so the proportion of successful collisions remains the same
5
Q
What is the effect of pressure of gaseous reactants on the rate of reaction?
A
- When pressure is increased, the gas particles occur in a smaller volume - packed closer together
- This increases collision frequency
- Increased pressure increases rate of reaction
- Increases collision frequency
- Speed of particles are the same so the proportion of successful collisions remains the same
6
Q
What is the effect of surface area of solid reactant on the rate of reaction?
A
- Increasing the surface area of a solid reactant means a greater surface exposed for collisions
- This means the collision frequency increases, as such there are more successful collisions
- Therefore a faster rate of reaction
7
Q
What is the effect of adding a catalyst on the rate of reaction?
A
- A catalyst is a substance that increases the rate of a chemical reaction without being changed in chemical composition or amount
- Catalysts work by providing an alternative reaction route of lower activation energy
- Increases rate of reaction
- More particles have sufficient energy so proportion of successful collisions increase
- Collision frequency remains the same