Try this out 5 - Empirical formula
A sample of aluminium oxide contains 1.08 g of aluminium and 0.96 g of oxygen. What is the empirical formula of this compound? [ Ar: O, 16; Al, 27 ]
Try this out 4 - Volume to mass
Calculate the mass of 2.8 dm3 of naphthalene, C10H8 at STP.
[Relative atomic mass: C=12; H=1; 1 mole of gas occupies 22.4 dm3 at STP]
(Ans: 16 g)
Try this out 3 - Mass to molecules
Calculate the number of water molecules in 90 g of water, H2O.
[Relative atomic mass: H=1; O=16; Avogadro constant, NA: 6.02 x 1023 mol-1]
(Ans; 3.01x 1024 molecules)
Try this out 2 - Mole to atom
1) Calculate the number of atoms in 0.2 mol of Copper atoms.
[Avogadro constant, NA: 6.02 x 1023 mol-1]
(Ans:1.204x 1023 molecules)
The atomic structure
is the symbol of aluminium. (a) Determine the number of neutron of aluminium.
(b) Write the electron arrangement of aluminium atom.
(b) Write the electron arrangement of aluminium atom.
(c) Write the valence electron of aluminium
Answer:
a) 27 - 13 = 14
b) 2.8.3
c) 3
Experiment-to determine the melting point of naphthalene
Diagram show the apparatus to determine the melting point of naphthalene.
(heating process)
Experiment-to determine the freezing point of naphthalene
Diagram show the apparatus to determine the freezing point of naphthalene.
Make sure you label the apparatus.
Matter
Element: (satu jenis shj)
sodium, Na; copper,Cu; hydrogen, H2; oxygen, O2 ;
Compound: (dua atau lebih jenis)
water, H2O; carbon dioxide, CO2; sodium chloride, NaCl
Typer of particles:
Atom: (satu sahaja)
sodium, Na; copper,Cu
Molecule: (dua atau lebih)
hydrogen, H2; oxygen, O2 ; water, H2O; carbon dioxide, CO2
Ion: (positive ion + negative ion)
sodium chloride, NaCl
sodium, Na; copper,Cu; hydrogen, H2; oxygen, O2 ;
Compound: (dua atau lebih jenis)
water, H2O; carbon dioxide, CO2; sodium chloride, NaCl
Typer of particles:
Atom: (satu sahaja)
sodium, Na; copper,Cu
Molecule: (dua atau lebih)
hydrogen, H2; oxygen, O2 ; water, H2O; carbon dioxide, CO2
Ion: (positive ion + negative ion)
sodium chloride, NaCl
Collision Theory
Experiment I (zinc powder + hydrochloric acid)
Experiment II (zinc granules + hydrochloric acid)
1) Rate of reaction of experiment I is higher than experiment II
2) Exp I using zinc powder has a smaller size of zinc compare to Exp II
3) Smaller size of zinc has larger total surface area in Exp I.
4) Frequency of collision between zinc and hydrogen ion higher in Exp I
Experiment II (zinc granules + hydrochloric acid)
1) Rate of reaction of experiment I is higher than experiment II
2) Exp I using zinc powder has a smaller size of zinc compare to Exp II
3) Smaller size of zinc has larger total surface area in Exp I.
4) Frequency of collision between zinc and hydrogen ion higher in Exp I
5) Frequency of effective collision between zinc and hydrogen ion higher in Exp I.
Proton number and nucleon number
Proton number (atomic number) = number of protons in its atom
Nucleon number (mass number) = total number of proton and number of neutron in its atom
Rate of reaction
Rate of reaction = change in a selected quantity / time taken
Rate of reaction increases when
- An increase in the total surface area of a solid reactant (smaller size of the reactant)
- An increase in the concentration of a reactant
- An increase in the temperature
- A catalyst (positive) used.
Diffusion of bromine gas in gas jar
Bromine is made up of tiny and discrete particles.
The bromine particles move quickly in between the air particles,
from high concentration area to low concentration area
The bromine particles move quickly in between the air particles,
from high concentration area to low concentration area
Isotope
Atom of the same element with same number of proton and different number of nucleon.
Examples:
Carbon-14 = to determine the age of bones
Cobalt-60 = to use for the treatment of cancer
Examples:
Carbon-14 = to determine the age of bones
Cobalt-60 = to use for the treatment of cancer
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