Reversible Reactions (Mock)

Explain dynamic equalibrium?

Dynamic equilibrium occurs in a reversible reaction within a closed system when the rates of the forward and backward reactions are equal, and concentrations remain constant. It is "dynamic" because both reactions continue, just at the same rate. The position can be shifted by changing pressure, temperature, or concentration.

What is the rate like through a reaction of A+B <--> C+D?

- Initially forward reaction is high

- Over time forward rate decreases, however this means the backwards rate is increasing

- Eventually we will reach equilibrium (where the forward and backward rates are equal)

What is the forward reaction and what does it do?

It is A+B and the rate overall reduces.

What is the backward reaction and what does it do?

It is C+D and the rate overall increases.

How do you alter the position of equalibrium to favour one of the reactions?

You can alter one of three main conditions:

1) Temperature

2) Concentration/pressure

3) Catalysts

Is the forward reaction exothermic or endothermic?

exothermic

Is the backward reaction exothermic or endothermic?

endothermic

What does an increase in temperature do to the reaction?

It favours endothermic direction, equilibrium shifts to favour this reaction.

What does an increase in pressure do to the reaction?

It favours the reaction that produces less molecules.

What does an increase in catalysts do to the reaction?

It speeds up by offering an alternative energy pathway with a lowered activation energy requirement. Therefore reaching equilibrium faster.

Dynamic equilibrium (short + simple words)?

When the forward and backward reactions of a reversible reaction occur at the same rate in a closed system.

Le Chatelier's Principle?

Changing one condition to alter the position of equilibrium and favour either the forward or backward reaction.

What is making ammonia(NH3) used for?

- Fertilisers

- Cleaning products

- Explosives

What percentage of all man-made power every year is the creation ammonia?

1%

What is ammonia's reaction (element form and word form)?

N2(g) + 3H2(g) <--> 2NH3(g) = Nitrogen + Hydrogen <--> Ammonia

What has a higher boiling point than hydrogen and nitrogen?

Ammonia

What temperature does it have to be for the ammonia reaction to take place?

As high as can get away with without exploding (high = rate is good) and as low as we can get away with (low = favours forward reaction).

Why is high pressure needed in a forwards reaction?

Because the forwards reaction produces less molecules so high pressure is needed.

What is bad about high pressure?

Hard to maintain and could explode.

What does ammonium nitrate do?

Violently explodes

What does ammonium sulphate do?

Not explode

Is ammonia dangerous?

Yes highly dangerous, especially in salts.