Chemistry

Chemical Reactions

• COLOUR CHANGE
• TEMP CHANGE
• A SMELL OR ODOUR
• FIZZING AND BUBBLING (EVERNESCANCE)

A CHEMICAL CHANGE= DIFFERENT PARTICLES ARE FORMED

Physical reactions

• Reversible
• Can be easily seperated
• No new substance made

PHYSICAL CHANGE: KEEPS THE SAME PARTICLES

Iron and sulpher experiment

The reaction with iron and sulpher is

Iron + sulpher   -----------> Iron Sulphide

We know a chemical change has occured because it is non- reversible, hard to seperate and no new substance has been made.

We know a compound has been made because the chemicls have reacted that way to make a compound. 

Magneseium and Oxygen

Magnesium + oxygen-----------> Magneseium Oxide

When we burn Magneseium we make a White powder which is heavier than the Magneseium coil itself.

Thermal Decomposition of Copper Carbonate

Thermal Decomosition is when you heat something up and all the individual components break down. In copper Carbonate there is Copper, Carbon,Oxygen

The missing mass of the copper carbonate has evapourated,

The law of Composition is that particles in copper carbonate are always present in the same proportion no mtter how much solid you use.

Hoffmann Voltmeter

Water is made up of Hydrogen and Oxygen. H20 so there is 2 times hydrogen and 1 oxygen.

We could spit up these elements by using Hoffmans Voltmeter.

So this is using energy in a form of electricity to split these elements up.

Stearic acid

For heating and cooling curves, you are more likely to have used Salol or Stearic acid. They are easily melted in a boiling tube placed in a beaker of hot water.Stearic acid has a melting point of about 69 degrees and salol has a melting point of 45. The temperature can be followed using a thermometer or temperature probe connected to a data logger. The liquid may be cooled by putting the boiling tube in a beaker of cold water or just leaving it in the air.

Rusting

Rusting= corrosion of Iron/steel

For rust to occur we need to have rain and some metal.

The experminet we did was to find how quickly different substances corrode an iron nail.

The COLD WATER will dissolve oxygen.

The BOILED WATER contains less dissolved oxygen

The thin layer of OIL will prevent oxgen re-dissolving in the cooled water

Different Seperating techniques

• Decanting- Insoluble solid from a liquid( Sand and water)
• Filtration- Insoluble solid and liquid ( sand and water)
• Evapouration- Solid form a solution( Salt from salt solution)
• Distillation- Solvent from a solution( Water from salt solution)
• Fractional distillation(Ethanol and water)
• Seperating funnel(Oil and water)
• Chromotography- Soluble soid(Mixture of food dyes)

Atoms, Elements, Compounds, Mixtures

Atoms- The smallest particle of an element that can exist.It cannot be broken down into anything smaller.An element is made up of atoms all the same type.

Mixture- The molecules are not chemically joined togethrer, they are just occupying the same space

Compound- is made when atoms of different elements join together by chemical bonds.

Metals and Non metals

Magnesium + oxygen-------> Magnesium oxide

Metal+ oxygen-----> Metal Oxide

Metal Oxide= Alkaline= purple

Sulpher+ oxygen------> Sulpher dioxide

Non metal oxide= acidic= red