AS Chemistry Formulae, Equations and Amounts of Substances

AS CHemistry

Pearson Edexcel International AS

, Unit 1 Unit 2

- Formulae, Equations - Energetics
and Amount of - Intermolecular forces
substance - Redox chemistry and
- Atomic structure and groups 1,2,7
the periodic table - Introduction to
- Bonding and structure kinetics and
- Introductory organic equilibria
chemistry and alkanes - Organic chemistry :
- Alkenes halogenoalkanes,
alcohols, and spectra

, Formulae,
Equations and
amount of
substance

,Atoms, Elements, and Molecules
Term Definition

Atom The smallest unit of an element

Element Elements are substances that contain only
one type of atom

Molecule A particle made of two or more elements
chemically bonded together

Compound A substance containing atoms of different
elements bonded together

Ion A substance of one or more atoms joined
together and have a charge

, Definitions Practice
Is the species an element, molecule, compound, or ion?

1) Ca
2) O2
3) H2O
4) Fe3+
5) Ne



Answers: 1) element 2) molecule 3) compound 4) ion 5) element

, Working out molecular formula
You will need to remember the formula for some familiar
compounds and be able to work out the formula for other
compounds using the periodic table.



H2O2 - Hydrogen Peroxide

HNO3 - Nitric Acid

H2SO4 - Sulfuric Acid

HCl - Hydrochloric Acid