Exercise on calculation of number of moles

NUMBER OF MOLES
1. Hiow many times two titanium atoms heavier than three oxygen atoms?

2. P, Q, and R are three elements. Relative atomic mass for R is 210. One R atom is three times heavier than one Q atom and one Q atom is two times heavier than one P atom. Determine the relative atomic mass for element P.

3. Determine the relative molecular mass for the compounds below:
a) methane, CH4 b) ethanol, C2H5OH
c) glucose, C6H12O6 d) sodium sulphate, Na2SO4
e) sodium thiosulphate hydrated, Na2S2O3.5H2O
f) cobalt chloride hydrated, CoCl2.6H2O
g) ammonium carbonate, (NH4)CO3
h) aluminium sulphate, Al2 (SO4)3 i) oxygen gas

NUMBER OF MOLES Vs NO. OF PARTICLES
1. Calculate the number of particles:
a) 0.22 mole of nitrogen dioxide, NO2
b) 2.75 mole of zinc ions, Zn2+
c) 0.5 mole of ammonium chloride, NH4Cl
d) 0.2 mole of bromine gas

2. Calculate the number of mole for the following subtances:
a) 7.224 x 1022 carbon atoms, C
b) 1.204 x 1024 oxygen gas
c) 9.632 x 1023 sulfur dioxide, SO2
d) 4.515 x 1024 ammonia gas, NH3

NUMBER OF MOLES Vs MASS (g)
1. Find out the mass of:
a) 2/5 moles of zinc, Zn
b) 0.025 mole of sulfur dioxide, SO2
c) 1.75 moles of oxygen gas
d) 2 moles of chlorine gas

2. Calculate the number of mole of:
a) 1.4 g of Iron, Fe
b) 7.2 g of glucose, C6H12O6
c) 2.4 g of hydrogen gas

3. Calculate the number of particles of:
a) 1.3 g of zinc, Zn
b) 6.9 g nitrogen dioxide, NO2
c) 38.5 g carbon tetrachloride, CCl4
d) 132 g ozon, O3
e) 7.1 g chlorine

4. Determine the subtances mass:
a) 3.01 x 1023 iron atoms, Fe
b) 1.806 x 1024 hydrogen atoms
c) i) 1.505 x 1023 urene molecules, CO(NH2)2
ii) N dlm CO(NH2)2
iii)peratus N dlm sebatian CO(NH2)2
d) 2.709 x 1022 oxygen molecules

NUMBER OF MOLES Vs MOLAR VOLUME
1. Find out the volume of gas at S.T.P. condition:
a) 0.7 g of nitrogen gas
b) 5.4 x 1022 nitrogen dioxide molecules, NO2
c) 1.4 g of carbon monoxide, CO

2. Calculate the number of molecules of the following subtances at room condition:
a) 120 cm3 of methane gas, CH4
b) 4 dm3 of ammonia gas, NH3
c) 36 dm3 of sulfur trioxide, SO3

3. Determine the mass of gas at S.T.P. condition:
a) 3.36 dm3 of ozone gas,O3
b) 448 cm3 of fluorine gas, F2
c) 1.12 cm3 of ethane gas, C2H6

CHEMICAL FORMULAE
Combine the ions below to form the compound and write their names.
1. Ca2+ + SO42+ 
2. Al3+ + NO3- 
3 Na+ + F- 
4. Fe3+ + Cl- 
5. Mg2+ + O2- 
6. Cu2+ + CO32- 
7. Pb2+ + Cl - 
8. K+ + Cr2O42- 
9. K+ + MnO4- 
10. Zn2+ + SO42- 

EMPIRICAL FORMULAE

1. 6.1 g of metal X combined with m gram of oxygen to form an oxide with formulaX2O5. Determine the value m.

2. 1.5 g of a hydrocarbon compound contains 0.3 g of hydrogen. If the relative molecular mass for the hydrocarbon compound is 30, calculate its:
i) empirical formulae
ii) molecular formulae for the hydrocarbon compound.

3. A hydrocarbon X contains 80% of caarbon and 20% of hydrogen. 1.5 g of the hydrocarbon occupies the volume of 1.12 dm3 at S.T.P. condition. i) Find the emperical formulae of hydrocarbon X.
ii) Find the relative molecular mass for hydrocarbon X.
iii) Determine the molecular formulae for hydrocarbon X.

Combustion of X in athe air produces carbon dioxide and water.
i) write the balance chemical equation.
ii) calculate the volume of carbon dioxide gas liberated.
v) Calculate the mass of water prodiced if 0.6 g of hydrocarbon X has burnt completely in air.

CHEMICAL EQUATIONS

1. Balance the following equation:
a) N2 + (g) H2 (g) NH3 (g)
b) C2H5OH (ce) + O2 CO2 (g) + H2O (ce)
c) MnO2 (p) + HCl (ak) MnCl (ak) + Cl2 (g) + H2O (ce)
d) Na2CO3 (ak) + HNO3 (ak) NaNO3 (ak) + CO2 (g) + H2O (ce)
e) C4H10 (g) + O2 (g) CO2 (g) + H2O (ce)




[NA= 6.02 x 1023 zarah]
[1 mol gas = 22.4 dm3] pd. s.t.p.
[1 mol gas = 24 dm3] pd. suhu / keadaan bilik

[H=1 ; C=12 ; N=14 ; O=16 ; F=19 ; Na=23 ; Al=27 ;
S=32 ; Cl=35.5 ; Ti=48 ; Fe=56 ; Co=59 ; Zn=65 ; Br=80]