AQA GCSE Single Science Chemistry: The rate and extent of chemical change

studied byStudied by 0 people
0.0(0)
learn
LearnA personalized and smart learning plan
exam
Practice TestTake a test on your terms and definitions
spaced repetition
Spaced RepetitionScientifically backed study method
heart puzzle
Matching GameHow quick can you match all your cards?
flashcards
FlashcardsStudy terms and definitions

1 / 7

flashcard set

Earn XP

Description and Tags

8 Terms

1

How would you calculate the mean rate of reaction?

Quantity of product formed or reactant used up/time

New cards
2

Which factors affect the rate of chemical change? And how?

  • Concentration (more reactant particles means more collisions)

  • Pressure (more particles within given volume, increased number of collisions)

  • Temperature (increased energy particles collide with and increased speed means more collisions)

  • Surface area (more surface particles can collide over)

  • Presence of catalyst (lowers activation energy, provides alternative reaction pathway)

New cards
3

Required practical for rate of reaction: Turbidity/colour change

  • Add 10cm³ of sodium thiosulfate solution, ensure concentration is known, to a conical flask atop a black cross

  • Add 10cm³ of hydrochloric acid

  • Swirl flask gently and start stopwatch. Stop the watch after cross can no longer be seen.

  • Repeat process with different concentrations of sodium thiosulfate solution

New cards
4

Define collision and activation theory

Collision theory - Chemical reactions can occur only when reacting particles collide with each other and with sufficient energy.

Activation energy - The minimum amount of energy required for reaction to take place

New cards
5

Define equilibrium and Le Chatelier’s Principle

Equilibrium - When the forward and backward reaction occur at the exact same rate

Le Chatelier’s Principle - When a change is made to a system at equilibrium, the system moves to counteract that change

New cards
6

What happens if you change the concentration (providing the system is at equilibrium)?

  • If the concentration of reactants is increased, more products will be formed

  • If the concentration of products is decreased, more reactants will react

New cards
7

What happens if you change the temperature (providing the system is at equilibrium)?

  • An increase in temperature means the endothermic reaction will be favoured.

  • A decrease in temperature means the exothermic reaction will be favoured.

New cards
8

What happens if you change pressure (providing the system is at equilibrium)?

  • An increase in pressure favours the side with the least amount of moles

  • A decrease in pressure favours the side with the most amount of moles

New cards
robot