Rate of Reaction Flashcards
What does rate of reaction depend on?
- Temperature
- Concentration
- Catalyst
- Surface Area
What is the rate of reaction formula?
Amount of reactant used or product formed
Time
What are the three ways to measure rate of reaction?
- Precipitation
- Change in mass
- Volume of gas given off
What are the problems with precipitation?
- Only works for initially transparent solutions
2. Subjective
What are the advantages of measuring change in mass?
- Rate of reaction graphs are easy to plot
2. Most accurate
What is the problem with measuring change in mass?
The gas is released straight into the room.
What instrument measures the volume of gas given off?
Gas syringe.
What is the problem with measuring gas given off?
Vigorous reactions will blow the plunger out of the syringe.
What catalyst is used in the decomposition of hydrogen peroxide?
Manganese (IV) oxide catalyst.
Why are gas syringes accurate?
They usually show volumes to the nearest millilitre.
Why does a higher temperature increase rate of reaction?
The particles move quicker and collide more often.
Why does a higher concentration increase rate of reaction?
There are more particles so collisions are more likely.
Why does a larger surface area increase rate of reaction?
There will be more area for particles to work on, so collisions are more frequent.
What does increasing the temperature do?
Increasing the temperature causes faster collisions.
What is the activation energy?
The minimum amount of energy needed by particles to react.
What are the conditions needed for reactions to happen?
- Collisions
2. With enough energy
What is a catalyst?
A catalyst is a substance which speeds up a reaction, without being changed or used up in the reaction.
What are the advantages of catalysts?
- Saves money (less operating time)
2. Sustainable development (lower temperature)
What are the disadvantages of catalysts?
- Expensive
- Each catalyst only works for one reaction
- Catalysts can be poisoned by impurities
What is an exothermic reaction?
An exothermic reaction is one which gives out energy to the surroundings usually in the form of heat and usually shown by a rise in temperature.
What are three types of exothermic reactions?
- Combustion
- Neutralisation
- Oxidation
What are everyday uses for exothermic reactions?
- Hand warmers
2. Self heating hot chocolate
What is an endothermic reaction?
An endothermic reaction is one which takes in energy from the surroundings, usually in the form of heat, and is usually shown by a fall in temperature.
What is an example of an endothermic reaction?
Thermal decomposition.
