Redox titrations can be used to find the amount of iron in a sample (or other reagents).
In these titrations Fe
is oxidised to Fe
by an oxidising agent:
The oxidising agent is usually acidified potassium manganate (VII) or pota
Catalyst = substance that speeds up
reaction without being used up.
They provide an alternative mechanism with
lower activation energy.
For an equilibrium, they speed up both
reactions equally and so
A catalyst is a substance that changes the speed of a chemical reaction, but is not used up in the reaction.
Catalysts that speed up reactions work by providing an alternative route with a lower activation energy (catalysts do not
alter G, H or S for a r
Chemsheets A2 038
SECTION 1 - INTRODUCTION
1) ELECTRON STRUCTURE & DEFINITION OF TRANSITION METALS
4s fills before 3d.
4s also empties before 3d.
Give the electron structure of the following atoms
Light is one form of electromagnetic radiation.
Light is only a very small part of the electromagnetic spectrum.
Electromagnetic waves consist of electric and magnetic fields
which are perpendicular to each other
Protons and neutrons can be regarded as spinning about
In many atoms these spins are paired against each other
and so the nucleus has no overall spin (e.g. 12C).
Chemsheets A2 029
1) THE ELECTROMAGNETIC SPECTRUM
Visible light is the form of light which we can see. It is a form of energy made up of waves known as electromagnetic
radiation. What we perceive as light is actually on