Reversible Reactions + Equilibrium (Unit 6)

Question 1

Define Anyhdrous

Answer 1

Not containing water

Question 2

Define Dynamic Equilibrium

Answer 2

1) The forwards and backwards reactions occur at the same rate of reaction AND occur simultaneously

Question 3

What is a feature of dynamic equilibrium

Answer 3

The concentrations of the reactants and products remain constant

Question 4

What type of reactions can reach dynamic equilibrium?

Answer 4

Reversible reactions only

Question 5

Where can one observe a reaction that has reached dynamic equilibrium?

Answer 5

In a closed system

Question 6

What is a closed system?

Answer 6

A container in which a chemical reaction takes place. The products and reactants cannot escape

Question 7

When will a reaction eventually reach equilibrium?

Answer 7

What will happen if a reversible reaction takes place in a closed system?

Question 8

What will happen if something affects equilibrium?

Answer 8

The equilibrium will change position, changing the AMOUNT of products and reactants (though it will remain CONSTANT)

Question 9

What is Le Chatelier’s Principle?

Answer 9

If a system is at equilibrium and a change is made to any of the CONDITIONS of the system, the system responds to counteract the change in conditions

Question 10

What must you do when given a symbol equation in an exam?

Answer 10

ENSURE IT IT BALANCED!!!

Question 11

How does increasing the surface area or introducing a catalyst affect the equilibrium?

Answer 11

• It does not affect the position of equilibrium
• both reactions, however, occur at an INCREASED RATE
• Equilibrium is thus reached quicker

Question 12

How would increasing the concentration of reactants affect the position of equilibrium?

Answer 12

1) The forward reaction is favoured and occurs at a faster rate
2) The equilibrium thus moves to the right (follows the direction of reaction favoured) where MORE PRODUCT is formed
3) This means there is a less amount of REACTANT
4) THUS, CONCENTRATION REMAINS THE SAME

Question 13

How would increasing the concentration of products affect the position of equilibrium?

Answer 13

1) The backward reaction is favoured and occurs at a faster rate (because more particles unit volume, more freq. succ. collisions)
2) The equilibrium thus moves to the left (follows the direction of reaction favoured) where MORE REACTANT is formed
3) This means there is a less amount of PRODUCT
4) THUS, CONCENTRATION REMAINS THE SAME

Question 14

(forward reaction exo, backward reaction endo)

How would increasing the temperature affect the position of equilibrium?

Answer 14

1) The backward/endothermic reaction is favoured (as more heat can be taken in), so it occurs at faster rate (since particles more energetic, more freq. succ. collisions)
2) The equillibrium thus moves to the left
3) This thus increases amount of reactants and decreases amount of product
4) Thus, TEMPERATURE IS MAINTAINED (as the increased rate of endo reaction takes in heat)

Question 15

What side of the reactions is favoured if the pressure is increased in a closed system?

Answer 15

• 1 moles of gas universally takes up same amount of gas for all gases
• There the more moles on one side, the more pressure.
• There for, the reaction rate of the side with more moles is INCREASED

Question 16

(there are more moles in reactants than products)

How would increasing pressure affect the position of equilibrium?

Answer 16

1) The forward reaction is favoured so occurs at a faster rate (since more particles per unit volume, more freq. succ. collisions)
2) Equilibrium thus shifts to the right
3) This results in the AMOUNT of product increasing, and since more REACTANT is used up at once, there is a smaller AMOUNT of reactant.
4) Thus, pressure remains same because there is an increased amount of product (which has less pressure since less moles- more product made compensates)