Chemistry - unit 1

Atom

The smallest piece of matter that can take place in a chemical reaction.

Element

A substance made up from only one type of atom.

Compound

A substance that has more than one type of atom chemically bonded together ONLY A DIFFERENT TYPE OF ATOM.

Molecule 

Two or more atoms chemically bonded. Differentiates from compounds as they can be different types of atoms or the same type of atom.

Chemical change

an irreversible change that produces a new substance. Occurs at the molecular level.

Physical change

a change of matter, not a new substance,concerned with energy too.

List some chemical changes

Combustion,frying an egg,rusting.

List some physical changes

melting,freezing,and vaporisation.

Aqueous

State of matter -dissolved in water

Group (Periodic Table)

a vertical column containing elements with similar chemical properties, due to having the same number of valence electrons

Period (Periodic Table)

A horizontal row in the periodic table, indicating the number of electron shells an atom has.

Atomic Number

The number of protons in the nucleus of an atom, which uniquely identifies an element.

Group 1

Alkali metals

Group 7

Halogens

Group 8

Noble gases

Group 2

Alkali earth metals

Group 3

Boron Group

Group 4

Carbon Group

Group 5

Nitrogen Group

Group 6

Oxygen Group

Periods (periodic table)

Periods are the horizontal rows of the periodic table, with each period corresponding to a new electron shell

Conservation of matter

The law that matter can change state and can’t be created or destroyed.

Name an example of conservation of mass through a chemical change

If you burn wood (chemical change) it creates new substances like ash and smoke   but if you measured all of them, the total mass would be the same as the original wood and oxygen used in the burning. The atoms are simply rearranged to form new compounds. 

test for hydrogen

Lit splint, squeaky pop. HCl + Mg→ H

test for oxygen

Glowing splint re-lights. H2O2 → H2O + O2

test for carbon dioxide

Limewater goes cloudy CuCO3 → CuO + CO2

What type of mixture can be separated using evaporation?

Solutions where the solute has dissolved in the liquid solvent.

What is chromatography?

2 solutes of a mixture. (2 soluble substances)

What is filtration?

Used to separate insoluble solutes from their solvent.

What is distillation & how does it work?

A separation technique used to separate liquids with different boiling temps.

What is a mixture?

A mixture is a material made up of two or more different substances (elements or compounds) that are physically combined but not chemically bonded together

What is evaporation?

A separation technique that requires to boil/heat the mixture and the solvent evaporates but the solute stays as it has a higher boiling point. (usually)

What is a chemical reaction?

The action of forming or breaking chemical bonds.

Give an example of a chemical reaction

Baking a cake, combustion, rusting of iron etc

What is the difference between a chemical change and reaction?

A chemical change (new properties) is the result of the chemical reaction (event).

What is thermal decomposition?

When a compound is broken down into two or more simpler substances once heated.