C8 - Rates and Equilibrium Flashcards
What is the rate?
Tells us how fast reactants turn into products.
What are the two equations for mean rate of reaction?
quantity of product formed/ time
quantity of reactant used up/ time
What is rate measured in?
g or cm^3/s
What are the 3 ways to measure rate?
- measuring the decreasing mass of a reaction.
-measuring the decreasing light passing through a solution.
-measuring the increasing volume of gas being given off.
a) using a glass syringe
b) using a measuring cylinder and trough.
For reactions to take place reactants must collide with?
Correct orientation and enough energy
Rate of reaction ____ if the frequency of successful collision ____.
Increase
What are the 5 factors that affect the rate of reaction by increasing frequency of successful collision?
Temperature
Surface area
Use of catalyst
Concentration of solutions
Pressure of gases
Why does rate of reaction increase when temperature increases?
Because particles have more energy and more around faster therefore particles collide more often and with more energy which increases the frequency of successful collisions.
Why does rate of reaction increase when concentration increases?
Because there’s more particles in a volume and therefore particles are closer together which increases the frequency of successful collisions.
Why does rate of reaction increase when a catalyst is introduced?
Because catalysts prouve an alternative route for the reaction with a lower activation energy which increases the frequency of successful collisions.
Why does rate of reaction increase when surface area of particles increases?
Because increase surface area means more particles are exposed therefore in contact with each other which increases the frequency of successful collisions.
Give examples of controlled reactions.
Nuclear to avoid explosions.
Rusting to reduce reactions by catalysts.
Mixing stuff to reduce time by giving more energy.
Combustion.
Food going bad by adding preservatives and reduce temp.
What is a catalyst?
A substance which increases the rate of reaction without being used up in the reaction.
Catalysts provide an alternative reaction route with a _____ activation energy.
Lower
What are examples of reversible reactions?
Melting and freezing
Neutralisation
What’s a word equation example of a reversible reaction?
Hydrated copper sulphate —-> anhydrous copper sulphate + water
What’s dynamic equilibrium?
When the reactants are turning into products at the same rate as the products are turning back into reactants.
What are the three affecting compositions of dynamic equilibrium?
Concentration, temperature and pressure
Who is le chatelier?
A french chemist who observed equilibrium mixtures.
What does yield mean?
Amount
How does concentration alter conditions?
Increasing the concentration of the reactant will ‘push’ or move the equilibrium to the product side as it opposes this increase and vice versa.
How does altering temperature affect conditions?
Increasing the temperature of the system will move the equilibrium in the endothermic reaction.
How does altering pressure change conditions?
Increasing the pressure of a system moves the equilibrium to the side with the fewer moles of gas and vice versa.
