reversible reactions + equilibria

reversible reaction

- a reaction where the products of the reaction

- can react with each other

- and convert back to the original reactants

what is the symbol for a reversible reaction

⇌

what 2 examples of reversible reactions do we need to know about

- the dehydration of hydrated copper (II) sulfate

- the effect of heat (thermal decompsotion) on ammonium chloride

what colour and state is ammonium chloride

white solid

describe the thermal decomposition of ammonium chloride (reversible)

- when ammonium chloride is heated it breaks down into ammonia gas and hydrogen chloride gas

- if you let it cool, the ammonia and hydrogen chloride react to re-form the solid

in the thermal decomposition of ammonium chloride, what is the forward reaction and what is the backward reaction

- forward reaction is when it breaks down into ammonia gas and hydrogen chloride gas

- so forward reaction is decomposition

- backward reaction is when ammonium chloride is re-formed

- so backward reaction is formation

when is hydrogen chloride called hydrochloric

when it is dissolved in water to form hydrochloric acid

ammonium chloride reversible reaction formula

NH₄Cl ⇌ NH₃ + HCl

copper sulfate reversible reaction formula

CuSO₄.5H₂O ⇌ CuSO₄ + 5H₂O

what is the forward and backward reaction in copper sulfate reversible reaction

- forward reaction = dehydration

- backward reaction = hydration

what are the conditions for equilibrium/ dynamic equilibrium

- reversible reaction

- in a closed system/ sealed container

what is a closed system

where none of the reactants or products can escape

equilibrium meaning

• the concentrations of reactants and products

• will reach a certain balance

• and stay there

characteristics of a reaction at dynamic equilibrium

- forward and reverse reactions occur at same rate

- the concentrations of reactants and products remain CONSTANT

what does the "position of equilibrium" in a reversible reaction depend on

- temperature

- and pressure

- of the reacting mixture

what is the position of the equilibrium

the relative amounts of reactants and products

what happens when you raise the temperature

- the endothermic reaction will increase

- to use up the extra heat

what happens when you reduce the temperature

- the exothermic reaction will increase

- to give out more heat

what happens if the equilibrium position moves to the right

the yield increases

what happens if the equilibrium position moves to the left

the yield decreases

yield

amount of product

what does an increase in pressure cause

the position of the equilibrium to shift to the side that produces fewer moles of gas

what does a decrease in pressure cause

the position of the equilibrium to shift to the side that produces more moles of gas

can the position of the equilibrium also be unchanged?

yes

does a catalyst affect the position of equilibrium in a reversible reaction and why/ why not?

- no

- because it speeds up the forward and backward reaction by the same amount

how do u answer an equilibrium question on temp

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how do u answer an equilibrium question on pressure

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