PAPER 2- rate and extebt if chemical changes Flashcards
What is the collision theory?
The more collisions, the faster the reaction is because energy is transferred during collisions
What four things affect the rate of reaction?
1) temperature
2) pressure/ concentration
3) surface area
4) catalyst
What is the equation to measure rate of reaction?
=amount of reactant used/ time
What are the 3 ways to measure rate of reaction?
Precipitation, change in mass, volume given off
How do you work out volume given off?
Use a gas syringe, the more gas given off, the faster the reaction
How do you carry out the reaction of magnesium and HCL to produce hydroden?
1) add set volume of HCL and place on a balance
2) add some magnesium ribbon and plug the flask with cotton wool
3) start stop watch and take readings at regular intervals
How do you carry out the practical of Sodium Thiosulfate and HCL to produce a cloudy precipitation?
1) Add a set volume of dilute sodium thiosulfate to a conical flask
2) Place on a piece of paper with a black cross on it
3) Add HCL to the flask and start the stopwatch
4) Now watch the cross disappear and stop the stopwatch
5) Repeat with different concentrations
What is a reversible reactions?
The products can react together to produce the origional
What is equilibrium?
forward reaction will be going the same rate as the backwards one
What does it mean if equilibrium lies on the right?
The concentration of the products is greater than that of the reactants
What does it mean when equilibrium lies on the left?
The concentration of the reactants is greater than that of the products
What does the position of equilibrium depend on?
1) Temperature
2) Pressure
3) Concentration
If the reversible reaction is endothermic one way, what is it the other way?
Exothermic
What is Le Chaterlier’s Principle?
The idea that if you change the conditions of a reversible reaction at equilibrium, the system will try counteract that change
In a reversible reaction what happens if you decrease the temperature?
equilibrium will move in the exothermic direction to produce more heat
