Equilibrium

Question 1

K= products/reactants
K gives an indication of equilibrium position
Only temperature effects value of k

Answer 1

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Question 2

Homogeneous: all species in the equation are in the same state (ie gases or all aq)

Answer 2

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Question 3

Heterogeneous: species in the equation are in different states

Answer 3

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Question 4

Of equilibrium is heterogeneous we have to be careful when writing equilibrium expression

• for heterogeneous equilibrium pure solids and liquids are omitted from the expression for K as their concentration is taken as constant and given value 1

This means that equilibrium is not affected by amounts of these substances

Answer 4

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Question 5

Effect of temperature on K

Answer 5

Endothermic cowards reaction:
Increased temperature favours products, yield of products increases so value of K increases

Exothermic forward reaction:
Increases temperature favours reactants so yield of products decreases so K decreases

Question 6

Bonds break in reactant molecules and form in product molecules

Answer 6

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Question 7

Learn molar bond enthalpy?

Answer 7

Enthalpy change when a bond in 1 mole of a gaseous molecule is broken or formed (usually an average/means)

Question 8

Bond breaking=endothermic

Bond making=exothermic

Answer 8

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Question 9

Enthalpy change= total bonds broken and total bonds made

Answer 9

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Question 10

Enthalpy of combustion is?

Answer 10

The enthalpy change when one mile of a substance is completely burned in oxygen

Question 11

Hess law defitnion

Answer 11

The enthalpy change of a chemical reaction depends only on the chemical nature and physical states of the reactants and products and is independent of any intermediate step