C6 - Rates Of Reaction - Needs Work Flashcards
What is a formulation
Mixture where components have specific purposes combined to make a useful product
Give 2 things needed for a chemical reaction to take place
Collision in the correct orientation
Sufficient activation energy
What is activation energy?
Minimum amount of energy needed for a chemical reaction to happen
What is the rate of reaction
Time taken for reactants to be used up/formulation of products etc
Give 4 things that affect rate of reaction
Temperature
Surface area
Catalysts
Concentration/pressure
How does temperature affect rate of reaction?
Increasing temperature gives particles more kinetic energy
Increases frequency of successful collisions
Rate of reaction increases
How does increasing surface area increase rate of reaction
Leads to more particles exposed
Increases frequency of successful collisions
Rate of reaction increases
How do catalysts increase rate of reaction
Provide a different pathway for the reaction to take place with a lower activation energy
Increase rate of reaction
How does increasing concentration/pressure increase rate of reaction
More particles in a specific volume
Increases frequency of successful collisions
Rate of reaction increases
Never write fractional answers when drawing tangents - only decimals
What is a reversible reaction
A reaction where there is a forward and backward reaction taking place at the same time
In a reversible reaction, one reaction is __ and the other is ____
Exothermic
Endothermic
What is dynamic equilibrium?
Rate of forward and backwards reactions are equal
So concentrations of reactants and products are constant (NOT AMOUNTS)
What type of system does dynamic equilibrium take place in?
A closed system
How can you create a closed system in an experiment
Lids on beakers
If temperature is increased which side (exo or endo) does equilibrium shift to (in an exam say left or right)?
Endothermic
Why does equilibrium shift to the endothermic side if temperature is increased
Rate of endothermic reaction increases - to counteract the effect of rising temperature I think?
Where does equilibrium shift to if pressure is increased?
To the side with the least moles
Yield on the side with the least moles increases (presumably the rate of the reaction towards this side increases therefore?)
What does the haber process do?
Method for the industrial production of ammonia
What is the forward reaction in the haber process
Exothermic
What is the reaction for the haber process
(g)N2 + 3H2(g) <=> 2NH3(g)
Give 2 ways the rate of reaction is I ncreased
Iron catalyst
High temperature
Why is temperature decreased
To increase Exothermic (forward) direction yield - increase ammonia yield
Why is pressure increased
Increase yield on the side with fewer moles (ammonia side)
What pressure is the haber process done at?
200 atmospheres
What temperature is teh haber process done at
450 degrees
Remaining hydrogen and nitrogen from the haber process is ___
Recycled
On cooling, ___ ammonia is removed
Liquid
Give the method for measuring rate of reaction by measuring volume of gas produced
- Measure 50 ml of HCl into a conical flask using a measuring cylinder
- Add a 1g strip of magnesium into the conical flask
- Start the stopwatch and record volume of gas release using a gas syringe every 10 seconds for 1 minute
- Ploy results on a graph of product formed over time and find the gradient to calculate rate of reaction
R. Repeat with different acid concentrations
Give a method for finding rate of reaction by checking for colour change
- Measure 50 ml of sodium thiosulfate solution into a conical flask with a measuring cylinder
- Place the conical flask on top of a printed black cross
- Measure 20ml HCl Ito a test tube and heat to 40 degrees with a water bath
- Add teh HCl, swirl and start the timer
- Time how long it takes for the cross to disappear by looking from above
- Repeat for other temperatures of HCl
- Plot a graph of temperature of reactants and rate of reaction (how long it took)
What was the traditional fertiliser
Manure
Give 3 things used in NPK fertilisers
Nitrogen
Phosphorus
Potassium
Give 3 ways NPK fertilisers benefit food production
Growing tastier and bigger and enhances productivity
How is nitrogen made
Made from ammonia from haber process
Give stages of forming ammonium nitrate
Haber process
Ammonia formed
Ammonia used to make nitric acid
React nitric acid with more ammonia to make ammonium nitrate fertiliser
Give a way ammonium nitrate is formed
Ammonia from haber process reacted with sulfuric acid
How is phosphorus obtained
From mined phosphate rock
Why can’t phosphate rock be used as a fertiliser?
Its insoluble
How is phosphorus made into a fertiliser?
Treated with nitric acid/Sulfuric acid to make a soluble salt for fertiliser
In what two forms is mined potassium found in
KCl or K2SO4
If energy change is positive in the forward direction, this reaction is endo/Exothermic?
Endothermic
what is rate of reaction measured in
g/s or cm cubed/s or mol/s
give 4 things affecting rate of reaction
pressure of reacting gases
surface area of solid reactants
temperature
presence of catalysts
