Test Week 3 Flashcards
1
Q
KINETIC THEORY
A
- Model about the structure of cases used to explain from of these common physical properties and behaviours
- First comprehensive version of this theory was printed in 1857 by RUDOLF CLAUSIUS
- Model states; gases are composed of particles have rapid constant motion
- No attractive force (attraction and repulsion)
- No fixed volume
- Collide at high speed
- Collisions are highly elastic
- KINETIC ENERGY and TEMPERATURE are proportional
2
Q
GAS
A
- Always take the shape of their container
- Very low density
- Exert pressure
- Can be compressed
- Readily diffuse through other gases
3
Q
IDEAL GAS
A
- No volume
- No attraction
- Never condense as particles don’t have volume
4
Q
REAL GAS
A
- Has volume
- Have forces of attraction
- Condense to form liquid
5
Q
HOMOGENEOUS
A
- Uniform composition
- Particles of the material are spread evenly throughout its entire volume
- Eg. Copper, Distilled Water, Mineral Water, Air
6
Q
HETEROGENEOUS
A
- Variable compostion
- Different particles that make up the mixture are distributed in distinct clumps within the substance
- Eg. Blood, Sugar dissolved in Water, Vinegar, Orange Juice, Alka-Seltzer tablet
7
Q
ELEMENT
A
- Substance that cannot be broken down into simpler substances by chemical means.
- Composed of atoms that have the same atomic number (same number of protons in its nucleus as all other atoms of that element)
8
Q
COMPOUND
A
- Pure substance
- Have fixed composition
- Consist of two or more different elements that are chemically combined in a definite whole number atomic ratio
9
Q
MIXTURE
A
- Can be separated by physical means
- When mixed, individual substances keep their properties in a mixture, while if they form a compound their properties can change
- There is little or no energy change when a mixture forms
- Variable compositions
10
Q
SOLUTION
A
- Homogeneous mixtures like sea water, H20 and brass are SOLUTIONS
11
Q
MOLECULES
A
- Things like H20 and C02
- MOSTLY made up of non-metals
12
Q
IONIC COMPOUND
A
- Metal and Non-Metal
- WHEN WRITING; put metal first (as its a cation)
- Eg. NaCl
- DONT PUT PREFIX
13
Q
METALLIC BONDING
A
- Between metals
14
Q
COVALENT
A
- Between 2 non metals
- WHEN WRITING; lowest group eg. CO2 not 02C
- Don’t use mono prefix for first element
- MONOXIDE NOT MONO OXIDE
- Shorten last element to ‘ide’
- Eg. N3Cl (Trinitrogren Chloride)
15
Q
COVALENT MOLECULAR
A
- 2 NON METALS
- PUT PREFIX ON FIRST ELEMENT EXCLUDING MONO
- A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms
- The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding.
16
Q
COVALENT NETWORK
A
- GRAPHITE, DIAMOND AND SILICON DIOXIDE
- A network solid or covalent network solid is a chemical compound (or element) in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material
- In a network solid there are no individual molecules, and the entire crystal may be considered a macromolecule
17
Q
JOHN DALTON (1766 - 1844) English Teacher & Scientist
A
- 1803 - 1808 published a precise definition of atoms THE ATOMIC THEORY
18
Q
THE ATOMIC THEORY
A
- Elements are composed of extremely small particles; atoms
- All atoms of a given element are identical; same size, mass and chemical properties
- Atoms of different elements have different size, mass and chemical properties
- Atoms are not created nor destroyed, or changed into different types during a chemical reaction
- Chemical reaction involves only SEPARATION, COMBINATION OR RE ARRANGEMENT of atoms
- Compounds are formed when atoms of more than one element combine in a specific atom
19
Q
J.J THOMPSON
A
- Matter was known to be electrically neutral
- Negative particles which made up cathode rays (ELECTRONS) has a mass of 1/1000(th) that of the smallest atom
- Proposed new model for the atom; PLUM PUDDING
- Model consisted of numerous small negatively charged electrons imbedded within a much LARGER uniform positively charged sphere
- WAS SHORT LIVED BY RUTHERFORD
20
Q
ERNEST RUTHERFORD (1871 - 1937) Physicist
A
- Proposed improved model (from Rutherford) of the ATOM that would account for his experiment observations
- Proposed the atom consisted mostly of empty space occupied by a very low mass of electrons
- The electrons orbited a tiny central region he called the NUCLEUS
- EXISTENCE OF ATOMIC NUCLEUS
- Worked on radioactivity, coining the terms ‘alpha’ and ‘beta’ to describe the two different types of radiation emitted by uranium and thorium
- He also observed that radioactive material took the same amount of time for half of it to decay, known as its “half life”
- That alpha particles through the gold foil deflected passed in the region where little electrons were
21
Q
SIR JAMES CHADWICK (1891 - 1974)
A
- Identified the neutrons as the product of alpha particle bombardment
- Finally accounting for the atoms mass (Rutherford model didnt have this)
- Awarded the Hughes Medal of the Royal Society in 1932
- Nobel Prize for Physics in 1965
22
Q
NIELS BOHR
A
- Modified Rutherfords model, solving problem of unstable electron orbits and accounting for the line of spectrum of hydrogen gas
- Proposed that electrons moved about the central nucleus in circular orbits
- Electron COULD orbit without loosing energy
23
Q
CURRENT ATOMIC MODEL
A
- Central nucleus where neutrons and protons are
- Electrons orbit within regions of characteristic electron distribution
- Electrons are tiny
24
Q
SPECTRAL ANALYSIS
A
- The analysis of a spectrum to determine the properties of its source, such as the analysis of the emission spectrum of a substance to determine the electron distribution in its molecul
25
PURE SUBSTANCE
- Having fixed or constant composition
- Not being able to separated into other substances by physical means
- Well defined and constant boiling point and melting point
26
SIEVING (PHYSICAL)
- Used to separate the components of a mixture based on PARTICLE SIZE
- Small particles pass through, whilst coarser grains don't
- Unlikely to produce pure substances
27
FILTRATION AND EVAPORATION
- Used to separate the substances in a mixture based on their differing solubility and volatility
- Other forms of filtration; micro filtration, ultrafiltration and nano filtration
28
GRAVITY SEPARATION
- Suitable for separating (or concentrating) components in a mixture based on their densities
- Effective when the components in the mixture have BIG DIFFERENCES IN DENSITIES e.g gold
29
DISTILLATION
- Used to separate a mixture based on boiling point differences in individual components of the mixture
- Process can be used to produce distilled water from sea water
