SCH4U Chemistry 12 Exam Questions Answered Correctly Latest Update 2025-2026
Rate of forward reaction decreases and the rate of reverse reaction increases - Answers As a
system approaches equilibrium...
1. Consistent observable properties
2. Closed system - Answers Characteristics of equilibrium
Reactants and products are all the same states - Answers Homogeneous equilibrium
Reactants and products are different states - Answers Heterogeneous equilibrium
Reaction is still occurring at microscopic level even though it appears to have completed -
Answers Dynamic equilibrium
Suniv = Ssys - Ssur - Answers 2nd law of thermodynamics
Solid->liquid
Liquid->gas
Solid dissolving
Temp increasing - Answers Processes that increase entropy
G=Hsys-T(Ssys) - Answers Gibbs free energy equation
Not spontaneous - Answers G>0
Spontaneous - Answers G<0
Reaction is at equilibrium - Answers G=0
- at all temps - Answers -H and +S
+ at all temps - Answers +H and -S
- at low temp - Answers -H and -S
- at high temps - Answers +H and +S
[Products] over [reactants]
Only uses equilibrium [ ]
*Coefficients are used at exponents* - Answers Kc expression
Products favoured - Answers Kc>1
, At equilibrium - Answers Kc=0
Reactants favoured - Answers Kc<1
Ignore change in concentration - Answers If Kc>500
[Products] over [reactants]
Uses any [ ]
*Coefficients are used at exponents* - Answers Qc expressions
Shift left - Answers Qc>Kc
No shift - Answers Qc=Kc
Shift right - Answers Qc<Kc
Add reactants = Shift right
Add products = Shift left - Answers Concentration shifts
Increase temp = Shift left
Decrease temp = Shift right - Answers Temperature changes (Exothermic)
Increase temp = Shift right
Decrease temp = Shift left - Answers Temperature changes (Endothermic)
Increase = Shift to LESS particles
Decrease = Shift to MORE particles - Answers Pressure changes
Increase = shift to MORE particles
Decrease = shift to LESS particles - Answers Volume changes
No shift - Answers Adding Inert Gas @ constant VOLUME
Shift to side with LESS particles - Answers Adding Inert Gas @ constant PRESSURE
Temp: 400-450
Pressure: 200atm
Catalyst: Iron (Fe3+) - Answers Haber process
Equilibrium: Decrease temp
Rate of forward reaction decreases and the rate of reverse reaction increases - Answers As a
system approaches equilibrium...
1. Consistent observable properties
2. Closed system - Answers Characteristics of equilibrium
Reactants and products are all the same states - Answers Homogeneous equilibrium
Reactants and products are different states - Answers Heterogeneous equilibrium
Reaction is still occurring at microscopic level even though it appears to have completed -
Answers Dynamic equilibrium
Suniv = Ssys - Ssur - Answers 2nd law of thermodynamics
Solid->liquid
Liquid->gas
Solid dissolving
Temp increasing - Answers Processes that increase entropy
G=Hsys-T(Ssys) - Answers Gibbs free energy equation
Not spontaneous - Answers G>0
Spontaneous - Answers G<0
Reaction is at equilibrium - Answers G=0
- at all temps - Answers -H and +S
+ at all temps - Answers +H and -S
- at low temp - Answers -H and -S
- at high temps - Answers +H and +S
[Products] over [reactants]
Only uses equilibrium [ ]
*Coefficients are used at exponents* - Answers Kc expression
Products favoured - Answers Kc>1
, At equilibrium - Answers Kc=0
Reactants favoured - Answers Kc<1
Ignore change in concentration - Answers If Kc>500
[Products] over [reactants]
Uses any [ ]
*Coefficients are used at exponents* - Answers Qc expressions
Shift left - Answers Qc>Kc
No shift - Answers Qc=Kc
Shift right - Answers Qc<Kc
Add reactants = Shift right
Add products = Shift left - Answers Concentration shifts
Increase temp = Shift left
Decrease temp = Shift right - Answers Temperature changes (Exothermic)
Increase temp = Shift right
Decrease temp = Shift left - Answers Temperature changes (Endothermic)
Increase = Shift to LESS particles
Decrease = Shift to MORE particles - Answers Pressure changes
Increase = shift to MORE particles
Decrease = shift to LESS particles - Answers Volume changes
No shift - Answers Adding Inert Gas @ constant VOLUME
Shift to side with LESS particles - Answers Adding Inert Gas @ constant PRESSURE
Temp: 400-450
Pressure: 200atm
Catalyst: Iron (Fe3+) - Answers Haber process
Equilibrium: Decrease temp
