Pages in this set

Page 1

Preview of page 1
Chemistry 2 Revision

Atoms




Mass number is always the biggest number
Mass number = relative atomic mass
Mass number ­ atomic number = neutron number
+ and ­ charges tell you what type of ion the atom will form in
a chemical reaction.
o In sodium metal (Na+) there are…

Page 2

Preview of page 2
Metal atoms lose the electron, or electrons, in their
highest energy level and become positively charged
ions.
Non-metal atoms gain an electron, or electrons,
from another atom to become negatively charged
ions.
E.g. A single crystal of salt is 1 giant ionic lattice, which is why
salt crystals tend to…

Page 3

Preview of page 3
o When dissolved the ions separate and are free to move in
the solution, so they'll carry electric current.
o Dissolved lithium salts are used to make rechargeable
batteries.
Conduct electricity when molten
o When an ionic substance melts, ions are free to move, and
they'll carry electric current.

Covalent…

Page 4

Preview of page 4
o Used for drill tips
o Has a very high melting point (almost 4000°C). Very
strong carbon-carbon covalent bonds have to be broken
throughout the structure before melting occurs.
o Is very hard. This is again due to the need to break very
strong covalent bonds operating in 3-dimensions.
o…

Page 5

Preview of page 5
Metallic Structures

Metals have giant structures
Metallic bonds have free electrons
The free electrons come from the outer shell of every metal
atom
The electrons are free to move and so metals are good
conductors of heat and electricity
These electrons also hold the atoms together in a regular
structure…

Page 6

Preview of page 6
when
molten




Nanomaterials

Really tiny particles
Fullerens molecules of carbon
Each carbon atom forms 3 covalent bonds, with its
neighbours, leaving free electrons that can conduct
electricity
Smallest fullerene is buckminster fullerene 60 carbon
atoms formed in a ball
Useful properties
o Have a huge SQ ­ help make great…

Page 7

Preview of page 7
Relative formula Mass (Mr)

Example:



MgCl2


24 + 12 + (35.5 x 2) = 95



CaCO3



40 + 12 + (16 x 3) = 100


Percentage Mass


A ×number of atoms
P ercentage mass = M rr of whole compound ×100

Empirical Formula

1) List all the elements in the…

Page 8

Preview of page 8
2) Underneath them, write their experimental masses or
percentages
3) Divide each mass or percentage by the Ar for that particular
element
4) Turn the numbers you get into a ratio by multiplying them by
numbers
5) Get the ratio in its simplest form

Example:

Find the empirical formula of…

Page 9

Preview of page 9
Example:

What mass of magnesium oxide is produced when 60g of magnesium
is burned in air?

1) Balanced equation



2Mg + O2 2 MgO



2) Work out the Mr:

2 x 24 2 x (24+16)

48 80

3) Rule: divide for fist then multiply



48g of Mg reacts to give…

Page 10

Preview of page 10
Mass in grams (of element of compound)
N umber of M oles = M r of element or compound




Example:

How many moles are there in 42g of carbon?

Number of moles = mass (g)/Mr = 42/12 = 3.5 moles



1 mole of solution contains 1 mole per litre



number…

Comments

mansi_xx

Report

Amazing! You just saved ma haha 

H.MBoss

Report

Ty

Tabz15

Report

Really, Really useful. I hope there is more of these for all 3 sciences and for all 3 units

Matt T

Report

This is absolutely brilliant, so helpful. Thanks a ton for this! :D

Kelleigh

Report


This is awesome!!

Jess

Report

Thanks!!!

11dohertyk

Report

Thanks :)))))))))))

holaat ur man 123

Report

your bare **** i love you sooooooooooooo much baby **

Similar Chemistry resources:

See all Chemistry resources »