How Fast? Flashcards
(24 cards)
What is rate of reaction?
Rate at which reactants are converted into products
What is the independent variable?
Variable you change in an experiment
What is the dependent variable?
The variable that changes as a result
What is a hazard?
Something that poses a risk
What is a catalyst?
A catalyst is a substance that speeds up a chemical reaction e.g. catalyst converter
It is not used up (it doesn’t absorb or breakdown)
Different reactions need different catalysts require
CATALYSTS LOWER ACTIVATION ENERGY
e.g. iron is a catalyst and makes ammonia from nitrogen and hydrogen
What does increase concentration do ?
More frequent collision of particles
High rate of reaction
Why is the rate of reaction quicker at the start?
More surface area
What factors and why increase rate of reaction?
Temperature - particles move more quickly. If they move faster they have more kinetic energy so they’re going to collide more frequently.
Concentration - too many particles therefore will collide more
Pressure of gases - too many particles therefore will collide more
Surface area - more particles are exposed e.g. crushed ice melts quicker than ice cubes
Catalysts - increase rate without being used up
What is the collision theory?
Chemical reactions only occur if reactant particles collide with enough energy
The more particles collide, the bigger the collision with enough energy, the greater the rate of reaction
How do you measure rate of reaction?
Measure rate at which reactant is used up
Measure rate at which produce is formed
What is rate of reaction of 24cm3 Hydrogen gas produced in 2 minutes ?
If formula:
Rate of reaction = reactant used or product formed / time
Then, 24 (product formed)/2 = 12cm3 hydrogen gas per minute
What are 2 ways we can measure rate of reaction
Rate of reaction = amount of reactant used / time
Rate of reaction = amount of product formed / time
Why is rate of reaction important in human body?
to supply your cells with exactly what they need when they need it.
Why is rate of reaction important in industry?
can develop methods to improve production
3 ways of measuring rate of reaction ?
Measuring mass of product over time
Measure mass of reactant over time
Measuring amount of light that passes through a reaction mixture over time
What does collision theory tell us about what needs to happen for a reaction to take place?
The particles need to collide, the more they collide, they more energy they produce and
the greater the rate of reaction
What is activation energy?
minimum energy required for a reaction to occur
What equipment can be used to measure mass of a product?
Balance
When is reaction complete?
No more reactant
2 ways which a reaction is formed?
Amount of reactant used
Amount of product formed
Describe how INCREASING TEMPERATURE affects rate of reaction in terms of FREQUENCY and ENERGY of collisions?
Rate increases as frequency and energy of collisions increase
Describe how DECREASE CONCENTRATION affects rate of reaction in terms of FREQUENCY and ENERGY of collisions?
Rate decreases as only frequency of collisions decrease
Describe how INCREASE GAS PRESSURE affects rate of reaction in terms of FREQUENCY and ENERGY of collisions?
Rate increase as only frequency of collisions increase
Describe how GRINDING UP CARONATE INTO A POWDER affects rate of reaction in terms of FREQUENCY and ENERGY of collisions?
Rate increase as surface area increases, increasing frequency of collisions
