Chemistry Paper 2 Topics Flashcards
What do steep lines mean on rates of reaction graphs?
Steep lines on reaction graphs = fast reaction
How can more products be formed in a reaction?
Increase products by increasing the reactants
What do flat lines represent on a rate of reaction graph?
Flat lines on reaction graphs mean that the reaction has stopped
What is activation energy?
Activation energy is the minimum amount of energy needed for particles to react
What two factors does the rate of reaction depend on?
The rate of reaction depends on collision frequency and collision energy
What is collision frequency?
The collision frequency is the number of collisions between particles in a reaction.
How does collision frequency affect the rate of reaction?
More collisions = faster rate of reaction (as there is more energy)
How does collision energy affect the rate of reaction?
Collision energy affects the rate of reaction as enough energy is needed to be transferred in a collision to overcome activation energy and break the bonds
How does temperature affect the rate of reaction?
Higher temp = faster rate of reaction
Lower temps = slower rate of reaction
How does concentration/pressure affect the rate of reaction?
High concentration/pressure = faster rates of reaction
Low concentration/pressure = slower rates of reaction
How does surface area affect the rate of reaction?
Large surface area = faster rates of reaction
Small surface area = slower rates of reaction
What is a catalyst?
A catalyst speeds up reactions by decreasing activation energy and providing an alternative pathway
How can we reach equilibrium in a reaction?
Equilibrium can be reached when a reversible reaction has taken place in a closed system
What is equilibrium?
Equilibrium is when both reactions happen and cancel each other out
What is a reversible reaction?
A reversible reaction is where the products can react to form the reactants again
Where does equilibrium lie if there are more reactants than products in a reaction?
The equilibrium lies on the left side of the reaction if there are more reactants than products
Where does equilibrium lie if there are more products than reactants in a reaction?
The equilibrium lies on the right side of the reaction if there are more products than reactants
What happens to the concentration of a reaction at equilibrium?
Concentration doesn’t change at equilibrium
What can happen if you change the reaction conditions of a reversible reaction?
Changing the reaction conditions of reversible reactions can cause the direction to change
Where does equilibrium lie if you cool the reaction?
Cooling the reaction means the equilibrium will lie on the left side of a reaction
Where does the equilibrium lie if you heat the reaction?
Heating the reaction means the equilibrium will lie on the right side of a reaction
What will the other direction be in a reaction if one is endothermic?
If one direction of a reaction is endothermic, the other reaction will be exothermic
What does le chatelier’s principle state?
le chatelier’s principle states that if the conditions in a reversible reaction at equilibrium are changed, the system tries to counteract that change
If the temperature of a reaction increases, what will the equilibrium shift to favour?
If the temperature of a reaction increases, the equilibrium shifts to favour the endothermic direction to take in heat energy
If the temperature of a reaction decreases, what will the equilibrium shift to favour?
If the temperature of a reaction decreases, the equilibrium will shift to favour the exothermic reaction to release heat energy
If the pressure increases in a reaction, what will the equilibrium shift to favour?
If pressure increases in a reaction, the equilibrium will shift to favour the side with fewer molecules of gas to reduce the pressure
If the pressure decreases in a reaction, what will the equilibrium shift to favour?
If pressure decreases in a reaction, the equilibrium will shift to favour the side with more molecules of gas to gain pressure
What happens if the concentration of a reagent is changed?
If the concentration of a reagent is changed, the system will respond to reverse the change
How will a system respond where there is an increase in the concentration of reactants?
If there is an increase in the concentration of reactants, the system will make more products
How will a system respond where there is a decrease in the pressure of reactants?
When there is a decrease in pressure of reactants, the system will make more reactants
What are flame tests used for?
Flame tests are used to test for cations in compounds
What colour flame will lithium appear as?
Lithium ions will have a red flame
What colour flame will sodium appear in?
Sodium ions will have a yellow flame
What colour flame will potassium appear in?
Potassium ions will have a purple flame
What colour flame will calcium appear in?
Calcium ions will have an orange flame
What colour flame will copper appear in?
Copper ions will have a green flame
What precipitate will form from sodium hydroxide + aluminium?
Sodium hydroxide + aluminium = white precipitate
What precipitate will form from sodium hydroxide + copper?
Sodium hydroxide + copper = blue precipitate
What precipitate will form from sodium hydroxide + Iron (Fe2+)?
Sodium hydroxide + Iron (Fe2+) = green precipitate
What precipitate will form from sodium hydroxide + Iron (Fe3+)?
Sodium hydroxide + Iron (Fe3+) = brown precipitate
What is the product of ammonium being warmed up? (NH4)
Ammonium will release ammonia gas when warmed up
How do we test for carbonate ions? (CO3^2-)
Carbonate ions can be detected using any dilute acid (Eg hydrochloric acid). Carbon dioxide bubbles will be produced when acid is added. Passing CO2 through limewater will also make it turn cloudy, therefore testing positive for the presence of carbon dioxide /carbonate ions
How do we test for sulfate ions in a solution? (SO4^2-)
We can test for sulfate ions in a solution by adding a few drops of dilute hydrochloric acid and dilute barium chloride solution.
Why do we add acid first in the tests for sulfate and halide ions?
Adding the acid first means that it can react with any carbonate ions that are present so there won’t be any fake results.