Chemistry - C3 Chemicals of the natural environment

Metallic bonding

This is a giant structure containing stationary positive metal ions and a sea of delocalized electrons. This creates strong forces of electrostatic attraction. This make metals generally solid at room temp, has high melting/boiling points, good conductors and malleable.

Ionic equations

Acid + Metal

→ Salt + Hydrogen

Water + Metal

→ Metal hydroxide + hydrogen

Ore

A rock that is typically a metal oxide and is economically worth extracting the metal from

Extracting with carbon

This only works for metals less reactive than carbon. The ore is heated with the carbon and the carbon displaces the metal in it, extracting the metal

phytoextraction

This involves growing a plant in an area of soil with metal compounds. The plant cannot get rid of the metal so it builds up in the leaves. These plants then can be harvested, dried and burned in a furnace and the ash will contain metal compounds.

Bioleaching

This uses bacteria to convert insoluble metal compounds in the ore to soluble compounds which extracts the metal in the process. leachate which is produced during the reaction contains an aqueous solution of metal ions.

Oxidation

loss of electrons

Reduction

gain of electrons

Cathode

the negative electrode where reduction occurs. This is where metals form during electrolysis

Anode

the positive electrode where oxidation occurs. This is where non-metals form during electrolysis.

Electrolysis (Molten)

This is the process of extracting metals from ores that are more reactive than carbon

Electrolysis (aqueous)

This is the process of extracting metals from ores that are more reactive than carbon but have too high a melting point to melt. at the cathode if H+ and metal ions are present hydrogen gas will be formed (if the metal is more reactive than hydrogen). Unless chlorine ions are present, oxygen will be formed at the anode.

Covalent bonds

When two non-metals bond together and share electrons on their outer shell

Dot cross diagram

a way of displaying covalent bonds

Displayed formula

a way of displaying covalent bonds

Ball and stick diagram

a way of displaying covalent bonds

Simple covalent structures

These are covalent structures that are only made up of a few atoms like water, oxygen and methane. They cannot conduct electricity and have low melting/boiling points as they have weak intermolecular forces.

Homologous series

A family of molecules that share the similar general formula and have the same functional group. They also carry similar properties. (For example alkane and alkenes)

Alkanes

These are the simplest homologous series. They have a general formula of **C***n***H***2n+2*. The shorter hydrocarbon chains are less viscous, are more volatile (Low melting/boiling point) and are more flammable. They all have c-c single bonds

Fractional distillation

This is the process of separating long chain hydrocarbons from short chain hydrocarbons. Long chain hydrocarbons have a higher boiling point so are collected at the bottom and short chain hydrocarbons have a lower boiling point so are collected at the top.

Crude oil

This is what is used in a fractioning tower. It provides the fuel for most modern vehicles and can be used to create new compounds like lubricants. However it is a finite resource and therefore non-renewable

Cracking

This is the process of splitting up long chain hydrocarbon. The hydrocarbons are heated then combined with wither a powdered catalyst or steam which splits them up. it produces a shorter alkane and an alkene. E.G. Decane → Octane + ethene

Alkenes

A homologous series of hydrocarbons that have a C=C double bond. They have a general formula of **C***n***H***2n*.

Bromine water + alkene

goes from orange to clear

Alcohols

These have a functional group of OH and a general formula of **C***n***H***n+1***OH** and are used as solvents and fuels. They are flammable can be dissolved into water and can be oxidised.

Carboxylic acids

These have a functional group of COOH and a general formula of **C***n***H***n+1***COOH**. They are weak acids that can dissolve in water and are used in foods and soaps