4.3 Rates of Reaction Flashcards
What is rate of reaction?
Change in quantity of reactants or products per unit time
What does collision theory state?
For a reaction to occur particles MUST have: at least an activation energy and collide
What does it mean if the collisions are more frequent/ faster?
Rate of reaction increases
Name 5 ways you can increase the rate of reaction?
- Increase the temperature
- Increase the SA of solids
- Increase concentration of solution
- Increase the pressure of gases
- Add a catalyst
How does increasing the concentration of a solution alter reaction rate?
- Increasing concentration of a solution increases the
rate of a reaction - There are more particles in the same volume
- There are more frequent collisions
- So there are more frequent successful collisions
How does increasing the surface area increase reaction rate?
- More particles are accessible at the surface
- There are more collisions per unit time
- There are more successful collision per unit time
How do you change the SA?
Make something larger or smaller
How does increasing the temperature increase reaction rate?
- Particles have more kinetic energy so there will be more frequent collisions
- A higher proportion of particles have at least the activation energy
- Therefore a higher proportion of collisions are successful
- There will be more successful collisions per unit time
What is a catalyst?
A chemical that speeds up a reaction without getting used up
How does a Catalyst affect the rate of reaction?
Provides an alternate reaction pathway with a lower activation energy
Name 3 catalysts?
- Manganese Oxide
- Iron Oxide
- lead Oxide
Which of the following increases the proportion of successful collisions?
a. Increasing surface area
b. Increasing temperature
c. Increasing concentration
d. Adding a catalyst
e. Increasing the pressure of a gas
a. X
b. Y
c. X
d. Y
e. X
Describe parts of the method for seeing how concentration affects the rate of reaction? (cross)
- Measure out 20 cm of HCL in a conical flask
- Place conical flask on black cross.
- 30 cm of distilled water to flask
- Add 10 cm of Sodium Thiosulphate to flask and start timer
- Wait for the cross to become non visible and record the time
What will you change when seeing how the concentration affects the rate of reaction?
Increase the volume of Sodium Thiophosphate
And decrease the volume of water
What is the Conclusion of the test of Concentration affecting the rate of reaction?
As the concentration increases the rate of reaction increases –> More Thiophosphate ions ions in the same volume meaning more frequent collisions
Describe parts of the method for seeing how Surface Area affects the rate of reaction? (upside down)
- Measure out 3g of CaCO3 in a conical flask
- Set up a delivery tube and an inverted 50cm measuring cylinder in water filled water trough
- measure out 20cm of HCL and pour in flask placing a bung on top.
What will you change when seeing how Surface Area affects the rate of reaction?
Size of the CaCO3 (marble chips) every time. 3x
Describe parts of the method for seeing how temperature affects the rate of reaction? (ribbons)
- measure 20cm of HCL
in a boiling tube - Cut pieces of Magnesium to 2cm
- Half fill a beaker with hot water to act as a water bath
- When HCL has reached a certain temp place on a test tube rack and place Mg to HCL.
- Stop timer when Mg has completely dissolves
What will you change when seeing how temperature affects the rate of reaction?
Change the temperature of HCL
What is the Conclusion of the test of temperature affecting the rate of reaction?
As temperature increases so will the rate of reaction
Give the test for carbon dioxide?
Bubble the gas through limewater, if it turns cloudy then CO2 is present
Give the test for Oxygen?
Re-light a glowing and if lights the O2 is present
