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Stoichiometry (moles) Cheat Sheet (DRAFT) by

Stoichiometry Moles Year-10 Topic-5 IGCSE

This is a draft cheat sheet. It is a work in progress and is not finished yet.

CHEMICAL FORMULAE & EQUATIONS

Valency
The number of electrons lost, gained or shared by an atom.
Chemical formula
The formula that represents the number & type of the atoms in a molecule.
Atomic groups
A set of atoms joined together that behave like one atom during a chemical reaction and they have their own valency & can't exist solely.
Chemical equations
A set of symbols and chemical formulae, repres­enting the reactants, products and the conditions of the reaction as well.
Reactants
The starting materials in a chemical reaction.
Products
The substances formed from a chemical reaction.
Valence shell
Outermost shell.
Valence electron
Electrons of the outermost shell (group number).
Period number
Number of shells.
1) GROUP NUMBERS: I II III IV V VI VII VIII.
2) Noble gases have zero valency (no gaining, losing or sharing electr­ons).
3) Prefix: Tells you how many atoms of each element in a formula.
1. Mono- 2. Di- 3. Tri- 4. Tetra- 5. Penta- 6. Hexa- 7. Hepta- 8. Octa- 9- Nona- 10. Deca-.
4) Non-metal ions take the suffix (ide). Chloride / Nitride / Oxide.
5) Methane --> CH
4
.
6) Zinc has a valency of 2.

ATOMIC GROUPS

ATOMIC GROUP
SYMBOL
CHARGE
VALENCY
Hydroxide
OH
-ve
1
Hydrogen carbonate
HCO
3
-ve
1
Nitrite
NO
2
-ve
1
Nitrate
NO
3
-ve
1
Ammonium
NH
4
+ve
2
Carbonate
CO
3
-ve
2
Sulfate
SO
4
-ve
2
Sulfite
SO
3
-ve
2
Phosphate
PO
4
-ve
3
Phosphite
PO
3
-ve
3
 

MOLES

Moles
A unit of measur­ement used in chemistry to express the amounts of a chemical substance.
Moles
The quantity of a substance that contains 6x1023.
Moles
The number of particles which is equal to the number of atoms in 12g Carbon.
Moles
The mass in grams which contains the Avogadro's constant number of particles.
Avogadro's constant
The number of particles in one mole of a substance.
Relative atomic mass
The average mass of the isotopes of elements.
Relative molecular mass
The sum of atomic masses of the elements in a compound.