1. 4S6
Welcome To the Chemistry World~

2. Cl-
Zn2+
Cl-
1 ZnCl2 = 1 Zn2+ ion 2 Cl- ions

3. 3.4 THE MOLE AND THE VOLUME
 - the molar volume of a gas is the volume
occupied by one mole of the gas or particles of
gas
 - one mole of any gas always has the same volume
under the same temperature and pressure.

4.  - the molar volume of any gas at STP is
22.4 dm3mol-1
________________.
 -Standard Temperature and Pressure (STP) is
0°C
the conditions where temperature is ______ and
1 atm
pressure is ________.
 Example:
22.4 dm3mol-1
 a. 1 mole of oxygen gas = _____________
22.4 dm3mol-1
 b. 1 mol of carbon dioxide gas= _____________
22.4 dm3mol-1
 c. 1 mol of ammonia gas = _______________

5.  - the molar volume of any gas at room temperature
24 dm3mol-1
is ________________.
 -At room temperature is the conditions where
25°C 1 atm
temperature is ______ and pressure is ________.
 Example:
24 dm3mol-1
 a. 1 mole of oxygen gas = _____________
24 dm3mol-1
 b. 1 mol of carbon dioxide gas= _____________
24 dm3mol-1
 c. 1 mol of ammonia gas = _______________

6. STP=22.4 dm3mol-1
Volume
RTP =24 dm3mol-1
Number of Molar
Moles volume
(More Van More Vibrate)

7. EXAMPLE 1:
 What is the volume of 2.5mol helium gas at
s.t.p? 22.4 dm3mol-1
Volume of gas
= No. of moles x molar volume
= 2.5 mol x 22.4dm3mol-1
= 56 dm3

8. EXAMPLE 2:
 What is the number of moles in 240 cm3 oxygen
gas at r.t.p? 24 dm3mol-1
number of moles
= volume of the gas
Molar Volume
= 0.24 dm3
24 dm3 mol-1
= 0.01 mol 240 cm3 = 240
1000
= 0.24dm3

9. EXAMPLE 3:
 Calculate the volume of the gases at room
temperature and pressure that contains:
a. 12 x 1022 C3H8 molecules
b. 2.4 x 1023 N2 molecules
(1 mole of gas occupies 24 dm3at room temperature;
NA= 6 x 1023 )

10. CALCULATE THE VOLUME OF THE GASES AT ROOM
TEMPERATURE AND PRESSURE THAT CONTAINS:
24 dm3mol-1
A. 12 X 1022 C3H8 MOLECULES
Number of mole
= 12 x 1022
6 x 1023
= 0.2 mol
Volume
= 0.2 x 24dm3
= 4.8dm3

11. CALCULATE THE VOLUME OF THE GASES AT ROOM
TEMPERATURE AND PRESSURE THAT CONTAINS:
B. 2.4 X 1023 N2 MOLECULES
Number of mole
= 2.4 x 1023
6 x 1023
= 0.4 mol
Volume
= 0.4 x 24dm3
= 9.6 dm3

12. ANSWER
a) Number of mole = 12 x 1022
6 x 1023
= 0.2 mol
1 mole of gas occupies 24dm3 at room temperature
0.2 mole gas occupies 0.2 x 24dm3 = 4.8dm3
b) Number of mole = 2.4 x 1023
6 x 1023
= 0.4 mol
1 mole of gas occupies 24dm3 at room temperature
0.4 mole gas occupies 0.4 x 24dm3 = 9.6 dm3

13. EXAMPLE 4:
 a. What is the volume of 4g of oxygen gas in cm3 at
STP?
 b. A sample of hydrogen gas contains molecules.
Find the mass of the hydrogen gas.
 c. How many molecules are there in 7840 cm3 of
ammonia gas in STP?

14. WHAT IS THE VOLUME OF 4G OF OXYGEN GAS IN
CM3 AT STP?
Number of mole
= 4g
32gmol-1
= 0.125 mol
Volume
= 0.125mol x 22.4 dm3 mol-1
= 2.8dm3
= 2800cm3

15. A SAMPLE OF HYDROGEN GAS CONTAINS 1.806 X
1023 MOLECULES. FIND THE MASS OF THE
HYDROGEN GAS.
Number of mole = 1.806 x 1023
6.02 x 1023
= 0.3 mol
mass of the hygrogen gas
= 0.3 mol x 2gmol-1
= 0.6g

16. C.HOW MANY MOLECULES ARE THERE IN 7840
CM3 OF AMMONIA GAS IN STP?
7840cm3 = 7840÷ 1000= 7.84dm3
Number of mole
= 7.84dm3
22.4dm3mol-1
= 0.35 mol
Number of molecules
= 0.35 mol x 6.02 x 1023
= 2.107 x 1023 molecules

17. a. Number of mole = 4g
32gmol-1
= 0.125 mol
0.125 mol of oxygen gas = o.125mol x 22.4 dm3mol-1 = 2.8dm3 = 2800cm3
b) Number of mole = 1.806 x 1023
6.02 x 1023
= 0.3 mol
0.3 mol of hydrogen gas = 0.3 mol x 2gmol-1 = 0.6g
c) 7840cm3 = 7840÷ 1000= 7.84dm3
Number of mole = 7.84dm3
22.4dm3mol-1
= 0.35 mol
0.35 mol of ammonia gas = 0.35 mol x 6.02 x 1023 = 2.107 x 1023
molecules

18. CHEMISTRY FORMULAE
 A CHEMICAL FORMULA is a representation of a
Chemical substance
_______________________ using symbols of the
elements and subscript numbers to show the
numbers of each type of atoms that are present in
the substance.

19. The overall charge
CHEMICAL FORMULA
must be 0
sodium chloride
+ -
Na Cl
NaCl

20. The overall charge
CALSIUM FLOURIDE
must be 0
2+ -
Ca F
CaF2

21. The overall charge
MAGNESIUM CHLORIDE
must be 0
2+ -
Mg Cl
MgCl2

22. The overall charge
MAGNESIUM SULPHATE
must be 0
Put in
2+ 2- simplest ratio
Mg SO4
MgSO4

23. The overall charge
ALUMINIUM OXIDE
must be 0
3+ 2-
Al O
Al2O3

24. The overall charge
AMMONIUM SULFATE
must be 0
+ 2-
NH4 SO4
(NH4 )2 SO4

25. The overall charge
LEAD (II) HYDROXIDE
must be 0
2+ -
Pb OH
Pb ( OH )2

26. NAMING
 Naming of cations of fixed oxidation state
 Naming of cations of variable oxidation state
 Naming of anions – ide
 ate- (Fat) – more oxygen
 Ite – (Fit )– less oxygen

27. CATIONS OF FIXED OXIDATION STATE
 Sodium ion (Na+)
Eg: Sodium chloride (NaCl)
 Magnesium ion (Mg2+)
Eg: Magnesium oxide (MgO)
 Calcium ion(Ca2+)
Eg: Calcium carbonate (CaCO3)
 Aluminium ion (Al3+)
Eg: Aluminium oxide (Al2O3)

28. CATIONS OF VARIABLE OXIDATION STATE
 Iron(ll) ion (Fe2+)
Eg: Iron(II) chloride (FeCl2)
 Iron(lll) ion (Fe3+)
Eg: Iron(III) chloride (FeCl3)
 Copper (l) ion (Cu+)
Eg: Copper(I) oxide (Cu2O)
 Copper (ll) ion(Cu2+)
Eg: Copper(II) oxide (CuO)
 Lead(ll) ion(Pb2+)
Eg: Lead(II) oxide (PbO)
 Lead(lV) ion (Pb4+)
Eg: Lead(IV) oxide (PbO2)

29. PREFIXES
 Mono 1
 Di 2
 Tri 3
 Tetra 4
 Penta 5

30. NAMING OF CHEMICAL COMPOUND
Fe2O3
O 2-
Fe3+
Iron(III) oxide

31. NAMING OF CHEMICAL COMPOUND
PbO2
O 2-
Pb4+
Lead (IV) oxide

32. NAMING OF CHEMICAL COMPOUND
 ZnO Zinc oxide
 NaNO3
Sodium nitrate
 SO3 Sulphur trioxide
 Fe2O3 Iron(III) oxide
 CCl4 Carbon tetrachloride
 N2O4 Dinitro tetraoxide
 CaCl2 Calcium chloride
 PbI2 Lead(ll) Iodide
 PbO2 Lead (IV) oxide
 K2CO3 Potassium carbonate
 PCl5 Phosphorus pentachloride

33. PASS UP ON MONDAY(4/3/2013)
Past year paper
Spotlight access 3.4
Spotlight access 3.5,
question8 and 9