Chapter11
Solution Composition:
A solute is the substance being dissolved.
The solvent is the dissolving medium.
When liquids are mixed, the liquid present in the largest amount is called
the solvent.
Ways of Expressing Concentration:
1) Molarity (M):
Molarity depends on the volume of solution, (Vsoln. = Vsolut. + Vsolvent.)
The molarity of the solution does change with temperature, however, because
the volume of the solution expands or contracts with temperature.
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1
,2) Mass by mass percent (g/g)
For example, a solution of hydrochloric acid that is 36% HCl by mass contains
36 g of HCl for each 100 g of solution.
(Solution = Solute + Solvent)
3) Molality (m)
molality depends on the mass of solvent
When water is the solvent, the molality and molarity of dilute solutions are
numerically about the same because 1 kg of solvent is nearly the same as 1 kg
of solution, and 1 kg of the solution has a volume of about 1 L
The molality of a given solution does not vary with temperature because masses
do not vary with temperature.
The molality is often the concentration unit of choice when a solution is to be
used over a range of temperatures.
4) Mole fraction (х):
The sum of the mole fractions of all components of a solution must equal 1:
XA + XB = 1
Mole fractions are very useful when dealing with gases .
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, Exercise: if a solution contains HCl (36.5 g) and water (144 g), then the mole
fraction of HCl (XHCl) and H2O (XH2O) equal:
Exercise: What is the molality of a solution made by dissolving 36.5 g of
glucose (C6H12O6) in 425 g of water?
Exercise: A solution is made by dissolving 4.35 g glucose (C 6H12O6) in 25.0 mL
of water. Calculate the molarity of glucose in the solution?
Exercise: A solution is made by dissolving 13.5 g of glucose (C 6H12O6) in
0.100 kg of water. What is the mass percentage of solute in this solution?
Exercise: Calculate the mass percentage of NaCl in a solution containing 1.50 g
of NaCl in 50.0 g of water?
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4
Solution Composition:
A solute is the substance being dissolved.
The solvent is the dissolving medium.
When liquids are mixed, the liquid present in the largest amount is called
the solvent.
Ways of Expressing Concentration:
1) Molarity (M):
Molarity depends on the volume of solution, (Vsoln. = Vsolut. + Vsolvent.)
The molarity of the solution does change with temperature, however, because
the volume of the solution expands or contracts with temperature.
Tariq Bataineh
1
,2) Mass by mass percent (g/g)
For example, a solution of hydrochloric acid that is 36% HCl by mass contains
36 g of HCl for each 100 g of solution.
(Solution = Solute + Solvent)
3) Molality (m)
molality depends on the mass of solvent
When water is the solvent, the molality and molarity of dilute solutions are
numerically about the same because 1 kg of solvent is nearly the same as 1 kg
of solution, and 1 kg of the solution has a volume of about 1 L
The molality of a given solution does not vary with temperature because masses
do not vary with temperature.
The molality is often the concentration unit of choice when a solution is to be
used over a range of temperatures.
4) Mole fraction (х):
The sum of the mole fractions of all components of a solution must equal 1:
XA + XB = 1
Mole fractions are very useful when dealing with gases .
Tariq Bataineh
2
,Tariq Bataineh
3
, Exercise: if a solution contains HCl (36.5 g) and water (144 g), then the mole
fraction of HCl (XHCl) and H2O (XH2O) equal:
Exercise: What is the molality of a solution made by dissolving 36.5 g of
glucose (C6H12O6) in 425 g of water?
Exercise: A solution is made by dissolving 4.35 g glucose (C 6H12O6) in 25.0 mL
of water. Calculate the molarity of glucose in the solution?
Exercise: A solution is made by dissolving 13.5 g of glucose (C 6H12O6) in
0.100 kg of water. What is the mass percentage of solute in this solution?
Exercise: Calculate the mass percentage of NaCl in a solution containing 1.50 g
of NaCl in 50.0 g of water?
Tariq Bataineh
4
