Chapter – Solutions ( 24 pgs shortened to 11pgs)
COMPONENTS OF A SOLUTION-
Solute and solvent are the components of a solution .( solute + solvent →
solution)
A solution is a homogeneous mixture of two or more substances . Solvent is
that component of a solution that has the same physical state as the solution
itself. Solute is the substance that is dissolved in a solvent to form a solution.
Solution concentration: - It is the amount of solute present compared
to the amount of solvent (or solution).. There are several ways to
describe concentration of solution: molarity, molality, normality,
mole fraction, mass percentage. (Normality is extra one)
1. Molarity: Molarity is the number of moles of solute dissolved per
litre of solution
- denoted by M
.
A 2.0 molar solution of sulphuric acid would be labelled as 2.0 M H2 SO4 .:
Prepared by: adding 2.0 mol H₂SO₄ to water to make 1 litre of a
solution.
Molarity changes with temperature due to expansion or contraction of
solution.
2. Molality : number of moles of solute dissolved per kilogram of
solvent.
- represented by symbol m
So molarility is how many moles of solute in Solution finally, but
molality is number of moles of solute in solvent.
Example: 2.0 m H₂SO₄ means 2.0 mol of H₂SO₄ in 1 kg of solvent
(read as “2 molal sulphuric acid”).
Normality is another concentration unit like molality,etc.. Normality- is the
number of gram equivalent weights of solute dissolved per litre of
solution.
Equivalent Weight- The number of parts by weight of a substance that
will combine with or displace 1.08 parts hydrogen, 8 parts oxygen, or
35.5 parts chlorine is called its equivalent weight..
basically it is the mass of a substance that reacts with a fixed
amount of another substance, , so they are calculated from the reactions
they take part in. this "fixed amount" was defined as the mass that would
, combine with or displace: 1.008 grams of hydrogen, 8 grams of oxygen, 35.5
grams of chlorine.
Equivalent weight is a number without units. when expressed in grams, it
is called gram equivalent weight.
Oxidising and reducing agents may have different equivalent weights
under different reaction conditions.
3 options. – 3 ways to calculate formula.
0.5 N KMnO₄ is read as “0.5 normal”
→ it contains 0.5 gram equivalent of KMnO₄ per litre of solution.
2. Mole Fraction : it is the ratio of its number of moles to the total number of
moles of all the components in the solution.
ex: If a solution contains 2 mol of alcohol and 3 mol of water, the mole
fraction of alcohol is 2 5 , and that of water 3 . 5 . Sum of mole fractions of
all components = 1
= so moles of solvent or
solute/total moles of component
Mass Percentage: It is the mass of solute present in 100 g of solution.
- Thus 5% solution of KMnO4 in water means that 5 g of KMnO4 is present in
100 g of the aqueous solution of KMnO4 .
Types of solutions :
Solutions can be gaseous,solid, liquid. Depending on the physical state of
solute and solvent, there are 9 possible types of binary solutions
COMPONENTS OF A SOLUTION-
Solute and solvent are the components of a solution .( solute + solvent →
solution)
A solution is a homogeneous mixture of two or more substances . Solvent is
that component of a solution that has the same physical state as the solution
itself. Solute is the substance that is dissolved in a solvent to form a solution.
Solution concentration: - It is the amount of solute present compared
to the amount of solvent (or solution).. There are several ways to
describe concentration of solution: molarity, molality, normality,
mole fraction, mass percentage. (Normality is extra one)
1. Molarity: Molarity is the number of moles of solute dissolved per
litre of solution
- denoted by M
.
A 2.0 molar solution of sulphuric acid would be labelled as 2.0 M H2 SO4 .:
Prepared by: adding 2.0 mol H₂SO₄ to water to make 1 litre of a
solution.
Molarity changes with temperature due to expansion or contraction of
solution.
2. Molality : number of moles of solute dissolved per kilogram of
solvent.
- represented by symbol m
So molarility is how many moles of solute in Solution finally, but
molality is number of moles of solute in solvent.
Example: 2.0 m H₂SO₄ means 2.0 mol of H₂SO₄ in 1 kg of solvent
(read as “2 molal sulphuric acid”).
Normality is another concentration unit like molality,etc.. Normality- is the
number of gram equivalent weights of solute dissolved per litre of
solution.
Equivalent Weight- The number of parts by weight of a substance that
will combine with or displace 1.08 parts hydrogen, 8 parts oxygen, or
35.5 parts chlorine is called its equivalent weight..
basically it is the mass of a substance that reacts with a fixed
amount of another substance, , so they are calculated from the reactions
they take part in. this "fixed amount" was defined as the mass that would
, combine with or displace: 1.008 grams of hydrogen, 8 grams of oxygen, 35.5
grams of chlorine.
Equivalent weight is a number without units. when expressed in grams, it
is called gram equivalent weight.
Oxidising and reducing agents may have different equivalent weights
under different reaction conditions.
3 options. – 3 ways to calculate formula.
0.5 N KMnO₄ is read as “0.5 normal”
→ it contains 0.5 gram equivalent of KMnO₄ per litre of solution.
2. Mole Fraction : it is the ratio of its number of moles to the total number of
moles of all the components in the solution.
ex: If a solution contains 2 mol of alcohol and 3 mol of water, the mole
fraction of alcohol is 2 5 , and that of water 3 . 5 . Sum of mole fractions of
all components = 1
= so moles of solvent or
solute/total moles of component
Mass Percentage: It is the mass of solute present in 100 g of solution.
- Thus 5% solution of KMnO4 in water means that 5 g of KMnO4 is present in
100 g of the aqueous solution of KMnO4 .
Types of solutions :
Solutions can be gaseous,solid, liquid. Depending on the physical state of
solute and solvent, there are 9 possible types of binary solutions
