Unit 2: Rates and Equilibrium Flashcards
What is the effect of pressure on the rate of reaction?
When the pressure of a gas is increased, the molecules are pushed closer together and rate of reaction increases because:
- the same number of molecules occupy a smaller volume
- for a gaseous reaction, increasing the pressure is the same as increasing the concentration
What is the effect of concentration changes on the rate of reaction?
if the concentration of the reactants are increased, the rate of reaction also increases. Because:
- increased concentration gives more molecules in the same volume
- the molecules will be closer together and therefore greater chance of molecules colliding
- collisions will be more frequent
What is a catalyst?
A substance that speeds up a reaction without being consumed by the overall reaction.
What are catalysts often?
Enzymes, generating specific products and operating effectively close to room temperatures and pressures.
What do catalysts affect?
The conditions that are needed.
They often require lower temperatures, reducing energy demand and CO2 emissions from burning of fossil fuels.
What do catalysts enable?
Different reactions to be used, with better atom economy and with reduced waste.
What is the effect of concentration changes on the rate of reaction?
if the concentration of the reactants are increased, the rate of reaction also increases. Because:
- increased concentration gives more molecules in the same volume
- the molecules will be closer together and therefore greater chance of molecules colliding
- collisions will be more frequent
What is the effect of pressure on the rate of reaction?
When the pressure of a gas is increased, the molecules are pushed closer together and rate of reaction increases because:
- the same number of molecules occupy a smaller volume
- for a gaseous reaction, increasing the pressure is the same as increasing the concentration
What is a catalyst?
A substance that speeds up a reaction without being consumed by the overall reaction.
What are catalysts often?
Enzymes, generating specific products and operating effectively close to room temperatures and pressures.
What do catalysts affect?
The conditions that are needed.
They often require lower temperatures, reducing energy demand and CO2 emissions from burning of fossil fuels.
What do catalysts enable?
Different reactions to be used, with better atom economy and with reduced waste.
What is Le Chatelier’s principle?
When a system is in dynamic equilibrium and is subjected to change, the position of the equilibrium will shift to oppose the change.
