Chemistry Revision

Front 1

Units of temperature
A. Converting Celsius to Kelvin
B. Converting Kelvin to Celsius

Back 1

A. Kelvin = C + 273
B. Celsius = K - 273

Front 2

Observations and inferences
A. What are Qualitative observations?
B. What are quantitative observations?
C. What is an inference?

Back 2

A. Describe what is observed.
B. Measure what is observed and numbers are used.
C. Explanation for observations. Based on past knowledge and experiences.

Front 3

What are the states of matter?

Back 3

Solid
Liquid
Gas
(All at room temperature)

Front 4

Physical Changes
A. Solid to liquid/ Liquid to solid
B. Solid to gas/Gas to solid
C. Liquid to gas/Gas to liquid

Back 4

A. Melting or liquefaction/Freezing or solidification
B. Sublimation (both)
C. Evaporation/Condensation

Front 5

Chemical Changes
What are the four indicators of a chemical reaction?

Back 5

Transfer of energy (heat or light)
Change in colour
Production of gas
Formation of a precipitate

Front 6

Mixtures
What is homogenous and heterogeneous mixtures?

Back 6

Homo - uniform composition, one phase
Hetero - not uniform throughout, more than one phase

Front 7

What is the law of conservation of mass?

Back 7

The mass of the reactants is always equal to the mass of the products. Mass is neither created or destroyed.

Front 8

Atomic Numbers and Mass Numbers, Explain
Electrons, Protons and Neutons
Elements are often symbolised with their mass number up the top and the atomic number on the bottom
Number of protons = number of electrons = atomic number
Number of neutrons = mass number - atomic number

Back 8

Electrons - negatively charged, smallest subatomic particle, exist on shells
Protons - positively charged, exist in nucleus
Neutrons - no charge, mass similar to protons, exist in nucleus

Front 9

Bohr - Rutherford Diagrams
Must know: number of protons, neutrons and electrons
Draw protons and neutrons in nucleus and electrons in the shells

Back 9

Draw Diagram of Calcium

Front 10

Isotopes
Same element with different number of neutrons, isotopes are chemically alike

Back 10

Examples

Front 11

Periodic Table
Elements are arranged in order of increasing atomic number
There are 7 rows, or periods, in the table

Back 11

Period 1 - 2 elements
Period 2- 8 elements
Period 3- 8 elements
Period 4- 18 elements
Period 5- 18 elements
Period 6- 32 elements
Period 7- 32 elements

Front 12

Periodic Table
Columns are known as groups
elements within a group have similar properties
there are three broad classes: metals, non-metals and mettaloids
Mettaloids generally have similar properties that are similar to those of metals and non-metals

Back 12

Physical Properties
Texture, mass, density, colour, state, melting and boiling points, harness, malleability, ductility

Front 13

Chemical Properties
Ability to combust,
oxidisation (rust),
reaction with chemicals

Back 13

Density
Ratio of the mass of an object to it's volume
density = mass/volume
density of pure water at 4 degrees Celsius is 1g/cm cubed

Front 14

Electron structure
electrons can be described as being located in different regions around the nucleus called electron shells
all of the electrons in a particular shell have similar energy and are approximately the same distance from the nucleus

Back 14

electrons closest to the nucleus have the lowest energy and strongest attraction to the nucleus and are most difficult to remove from the atom
electrons further away from the nucleus have more energy and have a weaker attraction to the nucleus, easiest to remove
max number of electrons a shell can hold = 2n squared
(n = shell number)

Front 15

Table of shell capacity

Back 15

Modern quantum mechanics describes regions of space around the nucleus known as orbitals, in which electrons exist as a "cloud"
Orbitals