S1.1 (Particulate Nature of Matter) Flashcards
Pure Substance
made up of one type of atom
Types of elements
monatomic, diatomic, polyatomic, allotropes
Allotropes
Alternative forms of an elemental substance
ex: graphite & Diamond
Mixture
More than one element non chemically bonded together
Homogeneous
- does not have a visible phase or boundary
- uniform composition
Heterogeneous
- has a visible phase or boundary
- non uniform composition
Filtration
- insoluble solid from a liquid
- ex: rocks & water
Distillation
- liquid from soluble solid/ liquids w different b.p (>50 degrees)
- ex: salt water
Fractional Distillation
- complex liquids
- close boiling points <25 Degrees
- ex: crude oil
Evaporation
- soluble solid from liquid
- ex: salt water
Chromatography
- seperates small quantities of substances
- stationary phase= paper; mobile phase= water
- RF Value = retention factor
Sublimation
solid -> gas
Melting/Boiling point
Temperature at which all particles have gained enough energy for the substance to change from solid-liquid/liquid-solid
Recrystallisation
- removes impurities mixed with a solid
- impure mixture is dissolved in hot solvent
- solution is cooled causing the solubility to decrease
- crstyals form -> soluble impurities are left
- impurities are filtered -> leaves pure solution
Solvation
- seperates heterogeneous mixture of two solids
- the two solids have a difference in solubility
- one is dissolved -> seperated by filtration
Kelvin
Based on particles kinetic energy (0K = 0 Kinetic Energy)
Deposition
Gas -> Solid
Celcius
based on the m.p & b.p of water
Relative Atomic Mass
The weighted mean mass of all naturally occuring isotopes of the element, relative to one twelth of the mass of a carbon atom
Kelvin to Celcius
- 0K = -273.15 C
- relative to eachother (increase by 1C = increase by 1K)
Rf value
retardation factor
Nematic liquid crytals
- 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
What happens to nematic liquid crystals when an electrical field is applied?
- 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
explain changes in particle arrangement and energy that occur when a solid is heated until it becomes a gas
- 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
Atom
The smallest unit of an element that retains chemical properties of that element, consisting of protons, neutrons and electrons
Ion
An atom or molecule that has gained or lost electrons, resulting in a net positive or negative charge
Molecule
A group of two or more atoms covalently bonded together, forming a. neutral particle with a defined structure
What to remeber when adding coefficinets when balancing equations
Add the 1
