Chemistry topic 6 Flashcards
how does something have a higher concentration/ pressure than something else
more particles in the SAME volume
how does increasing surface area effect rate of reaction and why
increased rate of reaction
more surface for the reaction to occur in
Leads to more frequent successful collisions
increased rate of reaction.
how does increasing temperature increase rate of reactions
- Particles gain more kinetic energy
- More likely for successful collisions to occur
- As more particles have energy greater than the activation energy
what do catalysts do
Catalysts increase the rate of chemical reactions but are not used up during the reaction.
how do catalysts work
Catalysts increase the rate of reaction by providing a different pathway for the reaction that has a lower activation energy.
give an example of biological catalysts
enzymes
what does it mean if something reacts in a closed system
reactants and products react in a closed container (nothing enters or escapes)
what does Dynamic equilibrium mean
rate of the forward reaction = rate of reverse reactions
what happens If a reversible reaction is exothermic in one direction and give the reason why
it is endothermic in the
opposite direction
If temperature is increased,
Position of equilibrium moves to the right
(more energy for the endothermic reaction to occur) Leads to more products being formed
what is Le Chatelier’s Principle
If a system is at equilibrium and a change is made to any of the conditions, then the
system responds to counteract the change
in Le Chatelier’s Principle what three conditions can be changed
- Concentration
- Temperature
- Pressure
do catalysts affect the position of equilibrium and why
Catalysts do NOT affect the position of equilibrium as it speeds up the rate of forwards and
backwards reaction at the same rate
what are Haber processes
the main industrial procedure for the production of ammonia
what is the equation for the Haber processes
nitrogen + hydrogen ⇌ ammonia
what are the conditions for the Haber process
- A temperature of 450oC
- A pressure of 200 atmospheres
- An iron catalyst
how can the rate of a chemical reaction be found
by measuring the quantity of a reactant used or the quantity of product formed over time.
what are the formulas or finding the mean rate of reaction
Mean rate of reaction = quantity of reactant used / time taken
Mean rate of reaction = quantity of product formed / time taken
what can the quantity of reactant or
product can be measured by
can be measured by
the mass in grams or by a
volume in cm3
what may the units of rate of reaction be
g/s or cm3/s.
Factors which affect the rates of chemical
reactions include what
- The concentrations of reactants in solution
- The pressure of reacting gases
- The surface area of solid reactants
- The temperature
- The presence of a catalyst
what is The minimum amount of energy that particles must have to react called
activation energy.
give the practical for the rate of reaction
1) Measure [50ml] of sodium thiosulfate
2) Place sodium thiosulfate in conical flask
3) Measure [10ml] of hydrochloric acid
4) Place on cross
5) Add hydrochloric acid to conical flask
6) Swirl
7) Start stopwatch
8) Measure time for cross to no longer be visible (this makes the practical subjective)
9) Repeat and find mean
10) Repeat for different concentrations of sodium thiosulfate/acid
Control variables
Concentration of hydrochloric acid
Volume of hydrochloric acid
Accuracy
Connect conical flask to a gas syringe
Measure time for fixed volume of gas to be produced
