rate of reaction Flashcards
What is the speed of a reaction called?
Rate
The rate of a chemical reaction is how fast the reactants are changed into products.
Name two types of reactions based on their speed.
- Slow (e.g., rusting)
- Fast (e.g., burning)
Different reactions occur at different rates.
What does a steeper line on a reaction graph indicate?
Faster rate of reaction
The line becomes less steep over time as reactants are used up.
What is collision theory?
A theory stating that a reaction will only occur when particles collide with enough energy.
This theory explains the rates of reaction in more detail.
What is the minimum amount of energy needed for a reaction called?
Activation energy
It is the smallest amount of energy particles need to react.
List the four factors affecting rates of reaction.
- Temperature
- Concentration of a solution (or pressure of a gas)
- Surface area of a solid
- Presence of a catalyst
Each factor can influence how quickly a reaction occurs.
True or False: Increasing the temperature decreases the rate of reaction.
False
When temperature increases, particles move faster and collide more frequently.
What happens to the rate of reaction when the concentration of a solution increases?
The rate increases
More particles in the same volume lead to more frequent collisions.
How does increasing the surface area affect the rate of reaction?
It increases the rate
More particles are available for collisions when a solid is broken into smaller pieces.
What is a catalyst?
A substance that speeds up a reaction without being used up
Catalysts provide a different pathway for reactions, lowering the activation energy.
What is the purpose of the practical experiment involving marble chips and hydrochloric acid?
To measure the rate of reaction producing CO2 gas
The experiment involves measuring the volume of gas produced over time.
What should be controlled in an experiment investigating the effect of acid concentration on reaction rate?
- Volume of acid
- Mass of marble chips
- Temperature
Only the concentration of acid should vary to ensure a fair test.
How can the amount of gas produced in a reaction be measured?
Using a mass balance
The mass of the reaction mixture will fall as gas escapes.
What is a precipitate?
A solid product formed in a reaction that makes a solution go cloudy
The reaction of sodium thiosulfate and hydrochloric acid produces a yellow precipitate of sulfur.
Fill in the blank: The faster the mark disappears in the sodium thiosulfate experiment, the ________ the reaction.
quicker
This indicates a faster rate of reaction.
What type of graph should be drawn to show the volume of gas given off during a reaction?
A graph with time on the x-axis and volume of gas on the y-axis
Crosses can be used to indicate the amount of gas produced at each time interval.
How can tangents be used on reaction rate graphs?
To compare reaction rates at different points
Tangents help visualize how the rate changes during a reaction.
What is the formula for calculating the mean rate of reaction?
Mean rate = Amount of reactant used or amount of products formed ÷ Time
This calculation provides an average rate over the reaction period.
How do you determine when a reaction has finished from a graph?
When the line goes flat
The flat line indicates that no more reactants are being used.
