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This video explains the mole concept.
This video shows you how to calculate the empirical formula of a compound.
These videos (Part 1 & 2) show you how to name & write the chemical formulae of ionic compounds.
These videos (Part 1 & 2) show you step-by-step how to write the chemical formulae of ionic compounds.
This video shows you how to write the chemical formulae of ionic compounds made up of polyatomic ions.
This video shows you how to balance chemical equations.
This video gives detail explanation on the 3 subatomic particles of an atom: protons, neutrons & electrons.
This video gives an introduction on what is an atom, explains the 3 subatomic particles of an atom: protons, neutrons & electrons, and shows how atoms bond to form molecules.
This video explains the atomic number (proton number) & mass number (nucleon number), and how to calculate the number of neutrons if both atomic number & mass number is given.
These videos explain what isotopes are.
Note: atomic number is also known as proton number; mass number is also known as nucleon number.
This video shows how to write electron configuration for Lithium, Carbon & Magnesium.
Note: For SPM exam, the way of writing the electron configuration (electron arrangement) is slightly different from this video. Dots are used to separate the number of electrons in each shell instead of using commas.
Example: Lithium has an electron configuration of 2.1
These videos explain how atoms form ions.
This video explains the characteristics of the 3 states of matter: solid, liquid & gas. It also explains 2 types of mixtures: homogeneous mixtures & heterogeneous mixtures.
This video gives a general explanation on what is an atom.
This video explains the differences between elements & compounds.
This video explains the differences between atoms, molecules, pure substances (elements & compounds) and mixtures (homogeneous & heterogeneous mixtures).
This video explains the Kinetic Molecular Theory (Kinetic Theory of Matter).
This video explains in detail how diffusion of gas occurs.
This video explains the properties of the 3 states of matter: solid, liquid & gas.
This video explains the arrangement of molecules in the 3 states of matter.
This video tutorial explains the changes between the 3 states of matter.
This video shows you how to read a heating & cooling curve.
This video gives you a general idea on what chemistry is about.
This video gives a general explanation on what is matter & how does energy affects the changes in the states of matter.
Note: SPM chemistry syllabus only focus on the 3 states of matter: solid, liquid & gas. The 4th state of matter – plasma mentioned in this video, is not included in the SPM chemistry syllabus.
These videos explain the physical changes & chemical changes of matter.
A chemical equation is a symbolic representation of a chemical reaction.
A chemical reaction is a process where one or more substances (reactants) changes into one or more new substances (products). In other words, reactants undergo a chemical change & transform into products in the end of the chemical reaction.
In a chemical equation, reactants are written on the left of an arrow, whereas products are written on the right of an arrow.
Step 1: Find the mass of each element.
Step 2: Calculate the number of moles of each element.
Step 3: Find the “mole ratio”.
Step 4: Find the simplest “mole ratio”.
Empirical formula is a chemical formula that shows the simplest ratio of atoms of each element present in a compound.
Molecular formula is a chemical formula that shows the actual number of atoms of each element present in one molecule of a compound.
The empirical formula of an ionic compound is similar to its formula unit.
Example: the empirical formula of sodium chloride is NaCl; the formula unit of sodium chloride is NaCl.
The molecular formula of a molecular compound is a multiple of its empirical formula.
Example: The empirical formula of Glucose is CH2O; the molecular formula of Glucose is C6H12O6.
Molecular Formula = n(Empirical Formula)
n = integer (1, 2, 3…)
What is the molar mass of Sodium, Water & Sodium Chloride?
[Relative atomic mass: H = 1; O = 16; Na = 23; Cl = 35.5]
Answer:
Molar mass of Sodium = Relative atomic mass of Na = 23 g mol-1
Molar mass of Water = Relative molecular mass of H2O = 1 + 1 + 16 = 18 g mol-1
Molar mass of Sodium Chloride = Relative formula mass of NaCl = 23 + 35.5 = 58.5 g mol-1
Note: Sodium is a metal made up of only Na atoms; Water is a molecular compound made up of H2O molecules; Sodium Chloride is an ionic compound made up of NaCl formula units.
Molar mass is the mass of one mole of a substance in grams.
*The unit of molar mass is grams per mole (g mol-1).
Molar mass of a substance is numerically equal to its relative atomic mass/ relative molecular mass/ relative formula mass.
Molar mass of atomic substance:
Molar mass of molecular substance:
Molar mass of ionic substance:
How to calculate the molar mass of different substances.
How many formula units are there in 1 mole of sodium chloride?
1 mol NaCl = 6.02 x 1023 NaCl formula units
*1 mole of sodium chloride contains 6.02 x 1023 NaCl formula units.
How many formula units are there in 2 moles of sodium chloride?
2 mol NaCl = 2 x 6.02 x 1023 = 1.204 x 1024 NaCl formula units
*2 moles of sodium chloride contains 1.204 x 1024 NaCl formula units.
How many ions are there in 2 moles of sodium chloride?
2 mol NaCl = 2 x 6.02 x 1023 = 1.204 x 1024 NaCl formula units
2 mol NaCl = 2(2 x 6.02 x 1023)= 2(1.204 x 1024) = 2.408 x 1024 atoms
*2 moles of sodium chloride contains 2.408 x 1024 ions (combination of Na+ ions & Cl– ions).
How many sodium ions are there in 2 moles of sodium chloride?
2 mol NaCl = 2 x 6.02 x 1023 = 1.204 x 1024 NaCl formula units
2 mol NaCl = 1(2 x 6.02 x 1023)= 1(1.204 x 1024) = 1.204 x 1024 Na+ ions
*2 moles of sodium chloride contains 1.204 x 1024 Na+ ions.
How many chloride ions are there in 2 moles of sodium chloride?
2 mol NaCl = 2 x 6.02 x 1023 = 1.204 x 1024 NaCl formula units
2 mol NaCl = 1(2 x 6.02 x 1023)= 1(1.204 x 1024) = 1.204 x 1024 Cl– ions
*2 moles of sodium chloride contains 1.204 x 1024 Cl– ions.
Note: 2 moles of sodium chloride contains 1.204 x 1024 Na+ ions & 1.204 x 1024 Cl– ions. Therefore, the total number of ions in 2 moles of sodium chloride is 2.408 x 1024 ions.
(1.204 x 1024) + (1.204 x 1024) = 2.408 x 1024 ions
How many molecules are there in 1 mole of water?
1 mol H2O = 6.02 x 1023 H2O molecules
*1 mole of water contains 6.02 x 1023 water molecules.
How many molecules are there in 2 moles of water?
2 mol H2O = 2 x 6.02 x 1023 = 1.204 x 1024 H2O molecules
*2 moles of water contains 1.204 x 1024 water molecules.
How many atoms are there in 2 moles of water?
2 mol H2O = 2 x 6.02 x 1023 = 1.204 x 1024 H2O molecules
2 mol H2O = 3(2 x 6.02 x 1023)= 3(1.204 x 1024) = 3.612 x 1024 atoms
*2 moles of water contains 3.612 x 1024 atoms (combination of hydrogen & oxygen atoms).
How many hydrogen atoms are there in 2 moles of water?
2 mol H2O = 2 x 6.02 x 1023 = 1.204 x 1024 H2O molecules
2 mol H2O = 2(2 x 6.02 x 1023)= 2(1.204 x 1024) = 2.408 x 1024 hydrogen atoms
*2 moles of water contains 2.408 x 1024 hydrogen atoms.
How many oxygen atoms are there in 2 moles of water?
2 mol H2O = 2 x 6.02 x 1023 = 1.204 x 1024 H2O molecules
2 mol H2O = 1(2 x 6.02 x 1023)= 1(1.204 x 1024) = 1.204 x 1024 oxygen atoms
*2 moles of water contains 1.204 x 1024 oxygen atoms.
Note: 2 moles of water contains 2.408 x 1024 hydrogen atoms & 1.204 x 1024 oxygen atoms. Therefore, the total number of atoms in 2 moles of water is 3.612 x 1024 atoms.
(2.408 x 1024) + (1.204 x 1024) = 3.612 x 1024 atoms
How many atoms are there in 1 mole of Magnesium?
1 mol Mg = 6.02 x 1023 Mg atoms
*1 mole of Magnesium contains 6.02 x 1023 Magnesium atoms.
How many atoms are there in 0.5 mole of Magnesium?
0.5 mol Mg = 0.5 x 6.02 x 1023 = 3.01 x 1023 Mg atoms
*0.5 mole of Magnesium contains 3.01 x 1023 Magnesium atoms.
How many atoms are there in 2 moles of Magnesium?
2 mol Mg = 2 x 6.02 x 1023 = 1.204 x 1024 Mg atoms
*2 moles of Magnesium contains 1.204 x 1024 Magnesium atoms.
How many atoms are there in 2 moles of Aluminium?
2 mol Al = 2 x 6.02 x 1023 = 1.204 x 1024 Al atoms
*2 moles of Aluminium contains 1.204 x 1024 Aluminium atoms.
Remember this formula:
Avogadro constant = 6.02 x 1023 particles per mole. Therefore:
This formula shows you how to calculate:
1) The number of particles (atoms, molecules or ions) when the number of mole is given.
2) The number of mole when the number of particles (atoms, molecules or ions) is given.
Depending on the type of substance, the particles in the substance can be atoms, molecules, or formula units.
For atomic substance, the particles in the substance are atoms.
*One mole of atomic substance contains 6.02 x 1023 atoms.
Example: 1 mole of iron contains 6.02 x 1023 Fe atoms.
For molecular substance, the particles in the substance are molecules. (Remember that a molecule is made up of 2 or more atoms.)
*One mole of molecular substance contains 6.02 x 1023 molecules.
Example: 1 mole of water contains 6.02 x 1023 H2O molecules.
For ionic substance, the particles in the substance are formula units. (Remember that a formula unit is made up of a cation & an anion.)
*One mole of ionic substance contains 6.02 x 1023 formula units.
Example: 1 mole of sodium chloride contains 6.02 x 1023 NaCl formula units.
One mole of a substance contains 6.02 × 1023 particles in the substance.
The number of particles in one mole of a substance is known as the Avogadro constant (also known as Avogadro’s number).
*The unit of Avogadro constant is particles per mole (particles mol-1)