Rates Of Reaction From Notes Flashcards
What are the four variables that affect the rate of a chemical reaction?
-temperature
-concentration of a reactant
-surface area/particle size
-Use of a catalyst
What must happen for a chemical reaction to take place?
For any chemical reactions to take place, the reacting particles must collide with enough energy in order to combine and for new products.
What is the relationship between temperature and the rate of reaction.
The higher the temperature, the faster the reaction.
The lower the temperature, the slower the reaction.
How does increasing the temperature increase the rate of reaction?
Increasing the temperature increases the rate of reaction because the particles collide with more energy.
What type of reaction can concentration be changed in?
Concentration can only be changed for reactions in solution.
How does an increase in reactant concentration increase the rate of reaction?
If the concentration of the reactants is increased, there are more reactant particles moving around in the same space. There will be more collisions and so the reaction rate is increased.
What is the relationship between concentration of reactant and the rate of reaction?
The higher the concentration of reactant, the faster the reaction.
The lower the concentration of reactant, the slower the reaction.
What type of reactants can particle size be changed in?
Particle size can only be changed for solid reactants.
What is the relationship between surface area/particle size and rate of reaction?
The greater the surface area, the higher the chance of collisions occurring and thus the faster the rate of reaction.
The smaller the particle size, the faster the reaction.
The bigger the particle size, the slower the reaction.
What is a benefit of catalysts?
Catalysts allow reactions to be carried out at lower temperatures, saving both energy and money.
What are enzymes and what is an example of their use?
Enzymes are biological catalysts. Enzymes can be used in industrial processes such as the fermentation of sugars to produce alcohol.
What are catalysts?
Catalysts are substances that speed up chemical reactions but can be recovered chemically unchanged at the end of the reaction.
What is the rate of a chemical reaction a measure of?
The rate of a chemical reaction is a measure of how fast the reactants are being used up or how fast the products are being made.
What three changes can be used to accurately measure the rate of chemical reaction?
To measure the rate of any reaction accurately, we can follow one of three changes:
-changes in the mass of the reactants or products
-changes in the volume of the reactants or products
-changes in the concentration of the reactants or products.
What formula is always used to calculate the average rate of a reaction?
Average rate(cm3/s)= change in measurable quantity(cm3)/ change in time(s)
What are marks awarded for when drawing a graph in exams?
-a suitable type of graph
-a suitable scale
-correct labels
-accurately plotted points/lines
