Rate and Extent of Chemical Changes Flashcards
How do you measure the rate of reaction?
Measure the rate at which the reactant is used up, and at which a product is formed (loss of reactants or gain of products).
What are the units for rate of reaction?
g/s, dm3/s, cm3/s - amount measured/time.
Three ways to measure the rate of reaction.
the rate at which a reactant is used up, or the rate at which a product is formed, gas produced, mass of products, time taken.
How can a change in pressure affect the rate of reaction?
Increasing the pressure on a reaction involving reacting gases increases the rate of reaction.
How can a change in surface area affect the rate of reaction?
The rate of a chemical reaction can be raised by increasing the surface area of a solid reactant.
How can a change in concentration affect the rate of reaction?
If the concentration of a dissolved reactant is increased, the rate of reaction increases.
What happens to ammonium chloride upon heating and cooling?
It decomposes when heated.
What happens to copper sulfate on the addition and removal of water?
It turns from blue (hydrated) to white (anhydrous).
What is Le Chatelier’s Principle?
When conditions are changed, the position of equilibrium changes to cancel out the change.
In an exothermic reaction, how does increasing temperature affect the yield produced?
Decrease.
In an endothermic reaction, how does increasing temperature affect the yield produced?
Increase.
In an exothermic or endothermic reaction, how does increasing concentration affect the yield produced?
Increase.
In an exothermic reaction, how does increasing pressure affect the yield produced?
Increase.
In an endothermic reaction, how does increasing pressure affect the yield produced?
Decrease.
What does a catalyst do?
It increases the rate of reaction without affecting the products.
What are the energy profiles for a catalysed and uncatalysed reaction?
Uncatalysed reactions have higher activation energy. Catalysed reactions have less activation energy (less increase on graph).
What does increasing pressure do to the equilibrium?
It shifts towards the side with fewer moles.
What does decreasing pressure do to the equilibrium?
It shifts towards the side with more moles.
What happens when you heat copper sulfate?
It turns from blue (hydrated) to white (anhydrous).
Why is the colour change of copper sulfate useful? What is another example?
It allows for a test for the presence of water. Cobalt chloride turns from blue to pink with water present.
