Chemistry -equilibrium exercises - calculating K solutions

Firstly - find the mole of carbon dioxide-- 44g/44 = 1mole

Next - via the equation find the mole of the other reactants and products present at equilibrium
Mole of ethane = 2 (we started with) - 0.5(reacted) = 1.5mole
Mole of oxygen=4 (we started with) - 1.75(reacted)= 2.25mole
Mole of carbon dioxide = 1mole
Mole of water = 1.5 mole water is produced

Next find the concentration of each
Concentration of ethane = 1.5/4 = 0.375M
Concentration of oxygen = 2.25/4 = 0.5625M
Concentration of carbon dioxide= 1/4 = 0.25M
Concentration of water = 1.5/4 = 0.375M

Next -place these values in the equilibrium expression

First - via the equation find the mole of the other reactants and products present at equilibrium
Mole of FeSCN = 1mole
Mole of Fe(III)= 2 (we started with) - 1(reacted)= 1mole
Mole of SCN = 4(we starated with) - 1(reacted) =1mole

Next find the concentration of each species present at equilibrium
Concentration of FeSCN = 1/2 = 0.5M
Concentration of Fe(III) = 1/2 = 0.5M
Concentration of SCN= 3/2 = 0.25M

Next -place these values in the equilibrium expression

Calculating "K"

Solutions

(click on the coloured cells for more information, double click to hide the information)

Equation	Equilibrium expression	K
		4.40 X 10^-3 M
2 mole of ethane and 4 mole of oxygen are mixed together in a 4 litre sealed container. At equilibrium it is found that 44 grams of carbon dioxide is present.
		0.660 M^-
2 mole of iron(III) ions and 4 mole of SCN ions are mixed together in a 2 litre sealed container. At equilibrium it is found that 1 mole of Fe(SCN) is present.
		7.30 X 10² M³
4 mole of ammonia and 4 mole of oxygen are mixed together in a 4 litre sealed container. At equilibrium it is found that 56 grams of nitrogen is present.
		0.125 M^-
2 mole of dinitrogen tetroxide are mixed together in a 1 litre sealed container. At equilibrium it is found that 92 grams of nitrogen dioxide is present.
		1.69M ²
3 mole of ammonia is placed in a 4 litre sealed container. The above reaction is allowed to reach equilibrium at which point it is found that 28 grams of nitrogen gas is present.

Back to the exercises

Home