Chemical Equilibrium (OG version)

Question 1

equilibrium

Answer 1

The exact balancing of two processes, one of which
is the opposite of the other

Question 2

chemical equilibrium

Answer 2

A dynamic state where the concentrations of all
reactants and products remain constant.

Question 3

• Irreversible reactions

Answer 3

Reactions in which the entire amount of the reactants are converted
into product

Question 4

• Reversible Reactions

Answer 4

A reaction which can be made to go in either direction

Answer 5

The rate (speed) of a reaction can be determined by the various concentrations of each species.

Question 6

equilibrium is reached when

Answer 6

The concentrations stay the same until something else happens to disturb this equilibrium.

Answer 7

The Equilibrium Constant is constant at
constant temperature.

Answer 8

The equilibrium constants changes as the temperature is varied.

We do not include the concentration
of pure solids or pure liquids in the
expression.

Question 9

• Homogeneous equilibria

Answer 9

– reactions occur in the same phase:

The position of a heterogeneous equilibrium does not depend on
the amounts of pure solids or liquids present.

▪ The concentrations of pure liquids and solids are constant.

Question 10

• Heterogeneous equilibria

Answer 10

– involve more than one phase:

Answer 11

K always has the same value at a given temperature regardless of the
amounts of reactants or products that are present initially.

• For a reaction, at a given temperature, there are many equilibrium

positions but only one value for K
.
▪ Equilibrium position is a set of equilibrium concentrations.

Answer 12

If K&raquo_space; 1 e.g. 108
. The ratio of product concentrations to
reactant concentration favours products.
Equilibrium lies to the right

Answer 13

If K &laquo_space;1 e.g. 10-10 .
The ratio of product concentrations to
reactant concentration favours reactants.

There is no relationship between the rate of reaction and the
numerical value of K.

Question 14

molarity

Answer 14

Also referred to as molar concentration
* Defined as the number of moles of solute dissolved in 1 litre of
solution
* Symbol M

C = n/v

The units are moles per litre (mol L
-1 or M)

c = concentration
n = number of mols (mol)
v = volume (L)

Question 15

Volumetric flask

Answer 15

A narrow-necked flask which can be used
to prepare an accurately known volume
of solution
* A graduation mark high on it’s neck
* When filled ‘up to the mark’, the flask
contains the volume given on the flask’
s
label

Question 16

diluting a solution

Answer 16

A solution of relatively high concentration can be diluted with the
same solvent to make a solution of the desired lower concentration

Answer 17

The choice of apparatus used depends on the precision
required

Question 18

Precision & accuracy

Answer 19

When a solution is diluted, the number of moles of solute
remains unchanged

Answer 20

Ionic compounds dissociate into their constituent ions when dissolved in
water.