Edexcel AS UNIT 2

A greater number of electrons and an increasing surface contact area (straight chain molecule)

High boiling point, high viscosity, high surface tension, unusually low density of ice, broad infra-red spectra absorption.

The energy released by the hydration of the ions.

They can all hydrogen bond with water, but the larger ones have large non-polar (hydrophobic) carbon chains.

Accepts electrons and gets reduced.

Donates electrons and gets oxidised.

Where the oxidation number of the SAME element both rises and falls in oxidation number.

It gets smaller as the atoms get larger as there are more electron shells and the outer electron becomes further away from the nucleus.

• Bonds in the substance have to break
• Bonds in the solvent have to break
• New bonds have to form between the substance and the solvent

A substance will only dissolve if the strength  of the new bonds formed is about the same as, or greater than, the strength of the bonds that are broken.

It increases

It decreases

It increases as the cations get larger and less polarising.

Electrons are excited by heat to higher energy levels. When they fall back they release photons of light of fixed energy and colour.

Thermal decompsition is when a substance is broken down when heated.

The more thermally stable a substance is, the more heat it will take to break it down.

A brown gas (nitrogen dioxide) and droplets of water at the mouth of the test tube if it is hydrated.