Rate Of Reaction Flashcards
Rate of reaction equals
Change an amount divided by change of time
In terms of particles, what is a high concentration
Concentration is the number of particles in a given volume. A high concentration means lots of particles in a given volume.
What is the effect of concentration on reaction rate?
An increase in concentration causes an increase in rate
Explain how increasing the concentration increases the rate of reaction
Increasing concentration means more particles per unit volume. This increases the frequency of collisions between reactants, and so the rate increases.
Explain how increasing pressure can change reaction rate
Increasing pressure increases rate of reaction particles are closer together, and so collide more frequently
What happens to the surface area of a solid acid is crushed from big pieces into a powder
It increases
Which has the largest surface area of small pieces or large pieces?
Small pieces
Explain how increasing the surface area increases the rate of reaction
Increase surface area means more particles are exposed on the surface of the solid. This increases the frequency of collisions between reactants, and so the rate increases.
During the reaction between sodium thiosulfate and hydrochloric acid, why do the mixture turn cloudy
Because sulfur is produced as a solid, and will not dissolve
What is activation energy?
The minimum amount of energy two particles need to have before they can react
What is a catalyst?
A catalyst is a substance that speeds up a reaction by lowering the activation energy, but it is not used up in the process
How does a catalyst speed up reaction?
It provides an alternative root for the reaction which has a lower activation energy
What effect does increasing the temperature have on reaction rate?
Increasing the temperature increases the reaction rate
Explain how an increased temperature can increase the reaction rate
Increase temperatures caused the particles to have more kinetic energy. This means they collide more often and I’m more likely to have the activation energy. This results in more frequent, successful collisions, and so the reaction rate increases.
Why is the rate of reaction fastest at the start?
Because the concentration of the reactants is highest then
