Equilibria

• What topic does this video cover from the AQA AS chemistry specification?

  Equilibria
• Why do students often find the equilibria topic challenging?

  It has specific answers AQA expects
• What is the significance of past mark schemes in studying equilibria?

  They reveal frequently expected answers
• What does the reversible reaction sign indicate?

  The reaction can proceed in both directions
• What is required for a system to be at equilibrium?

  It must be in a closed system
• What are two key properties of a reaction at equilibrium?

  Rates of forward and backward reactions are equal
• Why is the term "rate" important when discussing equilibrium?

  It indicates the occurrence of reactions
• What does Le Chatelier's principle state?

  Equilibrium shifts to oppose a change
• What happens when a factor affecting equilibrium is changed?

  Equilibrium shifts to counteract the change
• What type of changes can affect equilibrium?

  Temperature and pressure changes
• How does decreasing temperature affect the yield of methanol in the reaction?

  Yield of methanol increases
• Why does the equilibrium shift when temperature is decreased?

  It favors the exothermic reaction
• What is the enthalpy change for the forward reaction producing methanol?

  -49 kJ per mole
• What does an exothermic reaction release?

  Energy to the environment
• How does the equilibrium position change when temperature is decreased?

  It shifts towards the exothermic direction
• What is the relationship between the forward and backward reactions at equilibrium?

  Both reactions occur at equal rates
• How can the yield of methanol be increased in the reaction?

  By running the reaction at lower temperature
• What is the effect of increasing pressure on equilibrium?

  It shifts towards the side with fewer moles
• What is the significance of stating whether the forward or backward reaction is exothermic?

  It helps explain the shift in equilibrium
• How does the equilibrium shift when the temperature is increased?

  It shifts towards the endothermic direction
• What is the overall energy change in a reversible reaction at equilibrium?

  Energy remains constant
• What is the role of enthalpy change in determining reaction direction?

  It indicates whether the reaction is exothermic or endothermic
• If the pressure is increased in a reaction with equal moles of gas on both sides, what happens?

  No significant change in equilibrium
• Why is it important to understand the concept of dynamic equilibrium?

  It helps predict how changes affect reactions
• What topic does this video cover?

  Equilibria from unit 2 of AQA AS chemistry
• Why do students often struggle with equilibria?

  It can be complex but is straightforward
• How does the concept of equilibrium apply to real-world chemical processes?

  It helps optimize conditions for desired products
• What does the AQA mark scheme reveal about equilibria answers?

  There are specific answers expected repeatedly
• What is the definition of equilibrium?

  A state where forward and backward reactions equal
• What is required for a system to be at equilibrium?

  It must be in a closed system
• What happens to the equilibrium when temperature decreases?

  It shifts right to oppose the decrease
• Why does yield increase when temperature decreases in an exothermic reaction?

  Because the forward reaction is exothermic
• How can we increase methanol yield in an exothermic reaction?

  Run the reaction at a lower temperature
• What happens to the equilibrium when pressure increases in a gas reaction?

  It shifts to decrease the pressure
• Why does yield increase when pressure increases in a reaction with more moles on one side?

  It shifts right to reduce the volume
• What are two key properties of a reaction at equilibrium?

  Rates of forward and backward reactions are equal
• How many moles of gas are on the left side of the reaction?

  Four moles
• How many moles of gas are on the right side of the reaction?

  Two moles
• What does "dynamic equilibrium" mean?

  Both forward and backward reactions occur simultaneously
• What does a catalyst do to the position of equilibrium?

  It does not change the position of equilibrium