Chemistry GCSE: C6 The Rate and Extent of Chemical Change Flashcards
What do we call the substances that are used in a chemical reaction?
Reactants
What do we call the substances that are made in a chemical reaction?
Products
What are the four factors that affect the rate of a chemical reaction?
- The temperature of the reactants
- The concentrations of the reactants (or the pressure of a gas)
- The surface area of the reactants
- Catalysts
What is a catalyst?
A substance that speed up a chemical reaction
Without being used up
How do catalysts increase the rate of reaction?
They decrease the activation energy (the amount of energy needed for a collision to be successful).
So there are more successful collisions.
Ellie reacts 1.0M hydrochloric acid with magnesium.
What will happen to the rate of reaction if she tries 2.0M hydrochloric acid?
Explain why this happens.
The rate of reaction will increase.
- There will be more acid particles.
- Therefore there will be more collisons with magnesium particles.
- So there will be more successful collisons.
Charlie reacts sulfuric acid with calcium carbonate at room temperature (20oC).
What would happen to the rate of reaction if he repeated the reaction at 25oC?
Explain why this happens.
The rate of reaction will increase.
- At higher temperatures the particles have more energy.
- So they collide more.
- And the collisions are more energetic.
- So there are more successful collisions.
Milly reacts nitric acid with calcium carbonate chips (small pieces).
What would happen to the rate of reaction if Milly used calcium carbonate powder instead of chips?
Explain your answer.
The rate of reaction will increase.
- Powder has a larger surface area (to volume ratio).
- So there are more collisions.
- And more successful collisions.
James is reacting chlorine with magnesium.
What would happen to the rate of reaction if he added a catalyst?
Explain why this would happen.
The rate of reaction would increase.
- Catalysts decrease the activation energy.
- So there are more successful collisions.
Micah is reacting oxygen gas with magnesium.
What would happen to the rate of reaction if Micah increased the (gas) pressure of the oxygen?
Explain why this would happen.
The rate of reaction would increase.
- There would be more oxygen particles.
- So there would be more collisions.
- And more successful collisions.
In the graph below which line shows the fastest rate of reaction?
How can you tell?
The red line.
Because it’s steeper.
Look at the graph below showing how time affects the amount of product made.
The red line eventually starts to flatten. What does this mean? Why does it happen?
It means that the reaction has stopped (no more product is formed).
Because the rectants have all been used.
The graph below shows the carbon dioxide formed when hydrochloric acid reacts with calcium carbonate.
- Why does the line eventually flatten out?
- How would the line look different if a catalyst was added?
- Because the reactants (hydrochloric acid and calcium carbonate) have been used up.
- The first part of the graph would be steeper (faster rate of reaction). SEE GRAPH BELOW
The graph below shows the carbon dioxide formed when hydrochloric acid reacts with calcium carbonate.
- How would the graph look different if the temperature was increased?
- How would the graph look different if smaller pieces of calcium carbonate were used?
- The first part of the graph would be steeper (faster rate of reaction). SEE GRAPH BELOW
- The first part of the graph would be steeper (faster rate of reaction). SEE GRAPH BELOW
The graph below shows the carbon dioxide formed when hydrochloric acid reacts with calcium carbonate.
How would the graph look different if the concentration of hydrochloric acid was increased?
The first part of the graph would be steeper (faster rate of reaction) and the line would flatten out at a higher level (more product formed). SEE GRAPH BELOW