# Equations for Unit1&2

Needed.

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• Created by: Aisha
• Created on: 05-08-09 15:55
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## Pages in this set

### Page 1

Calculations

Relative Atomic Mass (Ar)

The Relative Atomic Mass, Ar, is the weighted average mass of an atom of an element, taking
into account its naturally occurring isotopes, relative to 1/12 of an atom of Carbon12.
Ar = Average mass of one atom of an element × 12
Mass of…

### Page 2

Calculations

Empirical Formula

The Empirical formula represents the simplest ratio of the atoms of each element present in a
compound.

Steps to work out the Empirical formula of a substance:
A sample of a hydrated compound was analysed and found to contain 2.10g of
Cobalt. 1.14g of Sulphur. 2.28g of…

### Page 3

Calculations

So, the molecular formula is the same as the empirical formula. C2H6O
The Ideal Gas Equation

If we take one mole of gas, the constant is given the symbol R and is called `the gas constant'.
For n moles of gas:

PV=nRT

Notes on Units...
o P must be…