S1.1 (Particulate Nature of Matter)

Question 1

Pure Substance

Answer 1

made up of one type of atom

Question 2

Types of elements

Answer 2

monatomic, diatomic, polyatomic, allotropes

Question 3

Allotropes

Answer 3

Alternative forms of an elemental substance

ex: graphite & Diamond

Question 4

Mixture

Answer 4

More than one element non chemically bonded together

Question 5

Homogeneous

Answer 5

• does not have a visible phase or boundary
• uniform composition

Question 6

Heterogeneous

Answer 6

• has a visible phase or boundary
• non uniform composition

Question 7

Filtration

Answer 7

• insoluble solid from a liquid
• ex: rocks & water

Question 7

Distillation

Answer 7

• liquid from soluble solid/ liquids w different b.p (>50 degrees)
• ex: salt water

Question 8

Fractional Distillation

Answer 8

• complex liquids
• close boiling points <25 Degrees
• ex: crude oil

Question 9

Evaporation

Answer 9

• soluble solid from liquid
• ex: salt water

Question 10

Chromatography

Answer 10

• seperates small quantities of substances
• stationary phase= paper; mobile phase= water
• RF Value = retention factor

Question 11

Sublimation

Answer 11

solid -> gas

Question 11

Melting/Boiling point

Answer 11

Temperature at which all particles have gained enough energy for the substance to change from solid-liquid/liquid-solid

Question 11

Recrystallisation

Answer 11

• removes impurities mixed with a solid

1. impure mixture is dissolved in hot solvent
2. solution is cooled causing the solubility to decrease
3. crstyals form -> soluble impurities are left
4. impurities are filtered -> leaves pure solution

Question 11

Solvation

Answer 11

• seperates heterogeneous mixture of two solids
• the two solids have a difference in solubility
• one is dissolved -> seperated by filtration

Question 12

Kelvin

Answer 12

Based on particles kinetic energy (0K = 0 Kinetic Energy)

Question 12

Deposition

Answer 12

Gas -> Solid

Question 12

Celcius

Answer 12

based on the m.p & b.p of water

Question 13

Relative Atomic Mass

Answer 13

The weighted mean mass of all naturally occuring isotopes of the element, relative to one twelth of the mass of a carbon atom

Question 13

Kelvin to Celcius

Answer 13

• 0K = -273.15 C
• relative to eachother (increase by 1C = increase by 1K)

Question 14

Rf value

Answer 14

retardation factor

Question 15

Nematic liquid crytals

Answer 15

• molecules that are linear or rod shaped/elongated in one direction
• molecules exhibit no positional order (free in space)
• molecules echibit partial directional order (tend to point in same direction)
  => more ordered than liquids but less ordered than solids

Question 16

What happens to nematic liquid crystals when an electrical field is applied?

Answer 16

• directional order increases significantly
• molecules align themselves more uniformly with the field direction
• alignment is due to molecules dipole moments interacting with the electrical field

Question 17

explain changes in particle arrangement and energy that occur when a solid is heated until it becomes a gas

Answer 17

• as a solid particles start to vibrate more vigourously in fixed position
• particles overcome forces holding them in fixed position causing melting
• further heating causes liquid particles to gain kinetic energy moving around eachother faster
• particles overcome intermolecular forces completely, becoming gas through boiling

Question 18

Atom

Answer 18

The smallest unit of an element that retains chemical properties of that element, consisting of protons, neutrons and electrons

Question 19

Ion

Answer 19

An atom or molecule that has gained or lost electrons, resulting in a net positive or negative charge

Question 20

Molecule

Answer 20

A group of two or more atoms covalently bonded together, forming a. neutral particle with a defined structure

Question 21

What to remeber when adding coefficinets when balancing equations

Answer 21

Add the 1