Rates And Equilibrium Flashcards
What does the rate of reaction tell you?
How fast reactants turn into products
How can you find the rate of a chemical reaction?
Monitoring the amounts of reactants used up over time
Measuring the amounts of products made over time
How do you calculate the rate on a graph?
Draw a tangent to the specific point, and calculate the gradient
Describe the shape of a volume of a gas produced / time graph
Increases, then curves and levels off
Describe the shape of a mass of reacting mixture / time graph
Starts high, decreases, then levels off
Quantity of reactant used (g) / time (s)?
Gives you the mean rate of reaction
What is the activation energy?
The minimum amount of energy that particles must have in order to react
Why does a larger surface area to volume ratio increase the rate?
If the substance is in smaller lumps/powder, each tiny piece of solid is surrounded by solution, and so many more particles of the solid are able to react at a given time
Why does an increased temperature increase the rate of reaction?
Particles collide more frequently and more energetically
A higher proportion of particles have energy greater than the activation energy
If you increase the temperature of a reaction by 10 degrees at room temperature, what will happen?
The rate will roughly double
Why does increasing concentration increase the rate of reaction?
There are more particles moving around in the same volume of solution. The more crowded together the particles are, the more frequent collisions will be
Why does increasing pressure increase the rate of reaction?
There are more particles of gas in a given space. The more ‘squashed together’ they are, the more frequent collisions will be.
Why does the presence of a catalyst speed up the rate of reaction?
Catalysts provide an alternate reaction pathway to the products, with a lower activation energy. So, with a catalyst, a higher proportion of the reactant particles have sufficient energy to react, there are greater frequency of effective collisions.
What happens to a catalyst during a chemical reaction?
It is not used up
It remains chemically unchanged
