2. SOLUTIONS
a homogenous mixture of particles.
made up of solute (lesser amount;
dissolved medium) and solvent
(greater amount; dissolving
medium)
6. SOLUBILITY
- maximum amount of solute dissolved
by a given amount of solvent at a
definite temperature
- a measure of the maximum amount of
solute that can be dissolved in a given
amount of solvent to form a stable
solution
7. TYPES OF SOLUTIONS
1. SaturatedSolution- holds the
maximum amount of
solute
2. UnsaturatedSolution - holds
less than the maximum
amount of solute
3. SupersaturatedSolution - holds
more than the maximum
amount of solute
8. FACTORS AFFECTING
SOLUBILITY
The larger the molecules of the solute
are, the larger is their molecular weight and
their size. It is more difficult for solvent
molecules to surround bigger molecules. If all
of the above mentioned factors ale excluded,
a general rule can be found that larger
particles are generally less soluble
10. FACTORS AFFECTING
SOLUBILITY
Liquids that are attracted by charged
objects are composed of polar molecules;
those that are not attracted by a charged body
are non polar.
12. FACTORS AFFECTING
SOLUBILITY
In endothermic process (heat is
absorbed) solubility increases with the
increase in temperature and vice versa.
For example: solubility of potassium nitrate
increases with the increase in temperature.
13. FACTORS AFFECTING
SOLUBILITY
In exothermic process (heat is released)
solubility decrease with the increase in
temperature.
For example:solubility of calcium oxide
decreases with the increase in temperature.
*Gases are more soluble in cold solvent than
in hot solvent.
17. - a unit for counting the number of particles
- 6.02 × 1023 particles (602, 000, 000, 000, 000,
000, 000, 000)
1 mole of oxygen atoms consists of 6.02 × 1023 atoms O.
1 mole of chlorine atoms consists of 6.02 × 1023 Cl.
1 mole of hydrochloric molecules consists of 6.02 × 1023 HCl.
1 mole of sodium chloride molecules consists of 6.02 × 1023 NaCl.
18. - a mole of atoms of any element will have a mass
in grams numerically equivalent to the element’s
atomic number; a mole of molecules of any
compound, will have a mass in grams numerically
equivalent to the compound’s formula mass or
molecular mass.
n
Molar mass is a mole of any substance in grams.
19. 1 mole O atom has a mass of 16 grams.
1 mole Cl atom has a mass of 35 grams.
1 mole HCl molecules has a mass of 36 grams
1 mole NaCl molecules has a mass of 58 grams.
20. - mole of any gas in an enclosed container, it
will occupy a volume of 22.4 litres at standard
temperature and pressure or STP (STP is 0oC
and 1 atm).
21. 1 mole H2 gas occupies a volume of 22.4 litres at STP.
1 mole He gas occupies a volume of 22.4 litres at STP.
1 mole Cl2 gas occupies a volume of 22.4 litres at STP.
1 mole O2 gas occupies a volume of 22.4 litres at STP
23. This is the mass of the solute divided by the
mass of the solution (mass of solute plus mass of
solvent), multiplied by 100.
Example:
Determine the percent composition by mass of
a 100 g salt solution which contains 20 g salt.
Solution:
20 g NaCl / 100 g solution x 100 = 20% NaCl
solution
24. Volume percent or volume/volume
percent most often is used when preparing
solutions of liquids. Volume percent is defined
as:
v/v % = [(volume of solute)/(volume of solution)]x100%
25. Example:
Wine is about 12% v/v ethanol. This
means there are 12 ml ethanol for every
100 ml of wine.
It is important to realize liquid and gas volumes
are not necessarily additive. If you mix 12 ml of
ethanol and 100 ml of wine, you will get less than
112 ml of solution.
26. Example:
70% v/v rubbing alcohol may be
prepared by taking 700 ml of isopropyl
alcohol and adding sufficient water to
obtain 1000 ml of solution (which will not
be 300 ml).
27. Molarity is probably the most
commonly used unit of concentration. It
is the number of moles of solute per liter
of solution (not necessarily the same as
the volume of solvent!).
28. Example: What is the molarity of a solution that
contains 10.0g of HCl (molar mass 36.5g/mol) per
liter of solution?
Solution:
First we find the number of moles of HCl equivalent
to 10.0g of HCl.
10.0g HCl × (1 mol HCl/36.5g HCl) = 0.274 mol HCl
With 0.274mol dissolved per liter of solution the
molarity is 0.274M in HCl.
30. BOILING POINT
The boiling point of a solution is
always greater than the boiling point
of a pure solvent. The greater the
quantity of solute present in a given
solvent the higher will be the boiling
point of the solution.
32. OSMOTIC PRESSURE
Osmosis refers to the movement
of solvent through a semi permeable
membrane from a region of low
concentration to a region of high
concentration.
33. VAPOR PRESSURE
The particles of pure water will tend to
evaporate faster than the particles of water in a
solution. This is because the interaction between
solute and solvent is stronger than the interaction
between solvent and another solvent. If
evaporation is faster in pure water, its vapour
pressure, its vapour pressure will be higher. Thus,
the vapour pressure of a solution is always lower
than the vapour pressure of pure solvent.
39. ACIDS AND BASES
Neutralization reaction between an acid
and a base, forming salt and water
Acids in the atmosphere are usually
produced by nitrogen oxides and sulfur
oxides that are released into the
atmosphere from the burning of fossil
fuels. They may be carried to the ground
by rain.