Chemistry 10

The law of conservation of mass

During chemical reactions or a change of state, no atoms are created or destroyed. The total mass of chemicals before and after a reaction stays the same.

FIlterisation

A physical separation process that involves removing insoluble particles from a mixture by passing it through a filtering medium.

Crystalisation

A separation technique of forming a solid from a liquid, solution, or gas.

Atomic Structure

- Dense nucleus

+ protons

- electrons 1/2000 mass of a neutron or proton

= neutrons

Electrons orbit in shells

Stability

All atoms want stability, so they lose or gain electrons to obtain a full outer shell for stability. They can be donated ( ionic) or shared ( covalent ).

Covalent bonds

Between two non-metals, a weaker structure, use prefixes for naming, share electrons

Ionic bonds

Between a metal and non-metal, lattice structure, metal - gas-ide, giving electrons

Nomenclature of transitional metals

The number of electrons donated is shown in brackets in roman numerals

CuO --> Copper ( II ) oxide

synthesis reaction

Two or more simple substances combine to a more complex product

C + O2 = CO2

decomposition reaction

A complex molecule is broken down into simpler substances

2H20 -> 2H + O2

displacement reaction

A more reactive element replaces a less reactive element from its compound.

Zn + Pb(No3)2 --> Zn(No3)2 + Pb

Zinc is more reactive than lead

Neutralisation reaction

acid + base = salt + water

HCL + NaOH --> NaCl + H2O

Salt formed from hydrochloric

chloride

Salt formed from nitric acid

Nitrate

Salt formed from sulfuric acid

Sulfate

Salt formed from Carbonic acid

Carbonate

Salt formed from acetic acid

Acetate

Acids Characteristics

Sour taste

turn blue limtus red

corrosive to metal

Produces H+

Indicators

Molecules that change different colours based on the acidity of the environment.

Found in leaves

what is pH

A measuring system for acidicity

How is pH measured

numbers from 0-14,

low numbers - acid

high numbers - basic

A neutral solution has a pH of 7

Acid + Metal

Salt + Hydrogen

Acid + Base

Salt + water

Acid + Carbonate

Salt + water + Carbon dioxide

Combustion reaction

Where oxygen is chemically combined with the atoms of a substance

What do combustions of metals form

Metal oxides

2Mg + O2 = 2MgO

Combustion of organic compounds (hydrocarbons)

Carbon dioxide + water

The carbon and hydrogen are oxidised

What does incomplete combustion create

Carbon monoxide + water or soot ( carbon )

How much energy does combustion need

A small quantity to begin, for example, striking a match

What does a combustion reaction emit

heat energy as it is exothermic

is used in transport, cooking, and electricity

Percipitation reaction

Two solutions combine to produce at least one soluble salt

Ba(NO3)2 + NaSO4 --> BaSO4 + 2NaNO3

NAGSAH what does it stand for ?

Nitrate

Acetate

Group 1

Sulfates

Ammonium

Halogens

What is NAGSAH used for

To determine whether ions will form an insoluble salt

Castro Bear

Calcium ( Ca )

Stronium ( Sr )

Barium ( Ba )

Purple mushrooms stink

Lead ( Pb )

Mercury ( Hg )

Silver ( Ag )

What is the exception for sulfates

Purple mushrooms stink

Castro Bear

What are the halogen exceptions

Purple mushrooms stink

What is an isotope

same atomic number different atomic mass.

can be unstable or stable

What do unstable isotopes do

they emit radiation, however, for some elements, all isotopes are radioactive or none

What is relative mass

A way of expressing the mass of an atom or molecule when comparing it to the mass of a single carbon-12 atom.

What is relative atomic mass

The measure of the average mass of an atom of an element, considering the abundances of isotopes

How to calculate relative atomic mass

Copper has 2 isotopes; 70% of the atoms are Cu-63 and 30% are Cu-65. Calculate the relative atomic mass of copper.

Relative atomic mass = (0.7 x 63) + (0.3 x 65) = 63.6