Prelims Flashcards
(139 cards)
1
Q
What does low ionisation energy mean for the element?
A
It is a metal
2
Q
What does high ionisation energy mean for the element?
A
It is a non-metal
3
Q
Atomic radius across a period
A
Decreases
4
Q
Atomic radius down a group
A
Increases
5
Q
ionisation energy
A
The energy required to remove one valence electron from a gaseous atom.
6
Q
electronegativity
A
The measure of the ability of an atom to attract electrons for chemical bonding
7
Q
what does high electronegativity difference between atoms indicate in terms of bonds?
A
more iconic bond
8
Q
what does low electronegativity difference between atoms indicate in terms of bonds?
A
more covalent bond
9
Q
features that affect electronegativity
A
as atomic radius increases, the electronegativity decreases, as its metallic charcter increases, the electronegavity increases
10
Q
periodicty
moving left to right (period)
trends?
A
Ionization Energy Increases
Electronegativity Increases
Atomic Radius Decreases
11
Q
periodicity
Moving up to down (groups)
trends?
A
Ionization Energy Decreases
Electronegativity Decreases
Atomic Radius Increases
12
Q
Carbonate
molecular formula
A
CO₃²⁻
13
Q
Phosphate
molecular formula
A
PO₄³⁻
14
Q
Nitrate
molecular formula
A
NO₃⁻
15
Q
Sulfate
molecular formula
A
SO₄²-
16
Q
Cyanide
molecular formula
A
CN-
17
Q
Sulfuric acid
molecular formula
A
H₂SO₄
18
Q
Nitric acid
molecular formula
A
HNO₃
19
Q
Nitrous acid
molecular formula
A
HNO2
20
Q
Phosphoric acid
molecular formula
A
H3PO4
21
Q
Acetic acid
molecular formula
A
CH₃COOH
22
Q
Glucose
molecular formula
A
C₆H₁₂O₆
23
Q
Acetate
molecular formula
A
C ₂H ₃O₂⁻
24
Q
hydrogen peroxide
molecular formula
A
H2O2
25
Salt
| molecular formula
NaCl
26
non-polar convalent bonds
electrons are shared equally
27
polar convalent bonds
electrons are not shared equally
28
H
| atomic number?
1.008
29
Na
| atomic number?
23
30
K
| atomic number
39.1
31
C
| atomic number
12.01
32
N
| atomic number
14.01
33
O
| atomic number
16
34
Cl
| atomic number
35.45
35
metaillic character
How close an element is to typical metallic properties - The metallic character of an element is proportional to its ability to lose electrons
36
ionic bonds
| what type of ions
metal + nonmetal
cation + anion
37
covalent bonds
non-metal + non-metal
sharing electrons
38
oxidation state
| increasing and decreasing means
A number or ‘charge’ assigned to an atom to indicate its degree of oxidation
It represents the charge an atom would have if all bonds were assumed to be ionic
An increase in oxidation state = oxidation
A decrease in oxidation state = reduction
39
Hydrogen in compounds
| oxidation state
+1
40
oxygen in compounds
| oxidation state number
-2
41
Rules to assign oxidation states
| 4
Atoms in an elemental state: oxidation number = 0
Monatomic ions: oxidation number = charge of ion
Polyatomic ions: sum of oxidation numbers = charge of ion (using algebra)
Neutral Compounds: sum of oxidation numbers = 0
42
types of intramolecular bonds
ionic, covalent, metallic
43
types of intermolecular forces
diple diple, hydogren, disperson,
44
dipole dipole bonds
one side of the molecule is slightly positive, and one side is slightly negative.
45
# *
45
hydrogren bonds
dipole-dipole interaction that occurs between hydrogen atoms bonded to either oxygen, nitrogen, or fluorine atoms
46
dispersion forces
exist between all molecules (doesn’t have to be ionic/polar), and occur due to the movement of electrons forming temporary dipoles.
47
phyical properties of elements/compounds due to intra/intermolecular forces
| mp, bp, forces
polar/covalent iconic compounds --> strong dipole dipole forces
nonpolar compounds --> weak dispersion forces
ionic and polar compounds tend to have higher melting and boiling points than nonpolar compounds. (due to strong bonds)
48
ionic network/compounds
| mp, bp, feature of bonds
form lattice structures
the attraction is equal in all directions, so the bond is non-directional.
--> makes the bonds very strong, so ionic compounds have high melting and boiling points
49
formula units
| ionic compounds
A single molecule of an ionic compound cannot exist, they always exist in lattices - so they are referred to as Formula Units instead of molecules, and are always in the simplest ratio
50
physical properties of ionic compounds
| electric conductivity, others
Solids --> poor electrical conductivity (no free electrions due to latice structure)
Molten --> good electrical conductvity (heat energy breaks lattice, ions can move)
Aqueous --> very good electrical conductivity (solid dissociates into its ions, more movement)
Solids--> brittle (displaces ionic layers, ions align in result, but others repel and break the solid)
51
Two methods of electrical conductivity
movement of electrons, or the movement of ions
52
Covalent molecular
exist as discrete molecules, with weak intermolecular forces between each molecule.
53
Physical properties of covalent molecular
| mp, bp, electricity condution
depending on strength, can be present as liquids, solids or gases --> wide range of mps & bps
no ions or free floating electrons --> do not conduct electricity
54
Covalent network
| examples
Bonded by covlent bonds in a continous network extending through the material
Can come as 2D or 3D networks
Graphite (2D), Diamond (3D) --> carbon allotropes
55
Graphite
occurs as stacked layers of carbon ina 2D hexagonal lattice strcuture
Within layers --> strong covalent bonds
Between layers --> weak intermolecular forces
layers slide over each other easily
56
Diamond
| features, physical properties
occurs as a tetrahedral structure
Strong covalent bonds everywhere
extremely hard
Not malleable
Non conductive
Extremely high mp and bp
57
Metallic bonds
| definiton, physical properties
A lattice of positive metal ions are held together by delocalised electrons (electron cloud/ electron sea) in metallic lattices.
Good electricity conducters --> declocalised electrons carry electricity
Good heat conductors --> carry heat in form of kinetic energy by moving around and hitting the colder parts of the lattice
Malleable/ductile --> when metal ions are displaced, the electron cloud acts as a ‘glue’ and stops the ions from repelling and breaking apart
58
allotrope
different structures of the same element
different physical and chemical properties
59
Hierachy of intermolecular forces in terms of strength
| Weakest to strongest
Dispersion, dipole dipole, hydogren bonding
60
shapes of covalent molecules
| names
Linear, trigonal planar, tetrahedral
others: trigonal pyramidal, sawhorse, T-shaped
61
# What shape if...
trigional plananr with 1 lone pair
| draw
bent
62
# What shape if...
Tetrahedral with 1 lone pair
| draw
triagonal pyramidal
63
# What shape if...
Tetrahedral with 2 lone lairs
| draw
bent
64
# What shape if...
Triagonal bipyramidal with one lone pair
| draw
saw horse
65
# What shape if...
Trigonal bipyramidal with 2 lone pairs
| draw
T-shaped
66
# What shape if...
Trigonal bipyramidal with 3 lone pairs
| draw
Linear
67
equation for moles using volume
| STP
volume of gas
_________________
22.71
68
equation for molar volume
| RTP
volume of gas
__________________
24.79
69
Theoretical yield
The maximum amount of product that can be produced
requires knowing the limiting reagent to be calculated.
70
Avogadro's gas law
equal volumes of different gases contain the same number of molecules.
(Volume is proportional to number of Moles)
V1/n1 = V2/n2
71
Boyle's law
The pressure exerted by a gas is inversely proportional to its volume when measured at a constant temperature
P1V1 = P2V2
72
Charles law
The volume of a gas is directly proportional to its temperature when measured at a constant pressure.
V1/T1 = V2/T2
73
Gay Lussac's law
The pressure exerted by a gas is directly proportional to its temperature (in Kelvin), when Volume is constant.
P1/T1 = P2/T2
74
Constant for calculating Kelvin from Celsius
273.15K
75
Ideal gas law assumptions
* The gas molecules move randomly in straight lines
* Pressure is due to collisions between the walls of the container and the molecules
* All collisions are perfectly elastic
* There are no intermolecular forces between gas molecules
* The gas molecules themselves take up no volume
76
Gas constant R
8.314/mole/K
77
standard solution
a solution of known and fixed concentration. A known weight of solute is dissolved to make a specific volume.
78
Primary standards
a reagent which can be weighed easily, and which is so pure that its weight is truly representative of the number of moles of substance contained.
used to prep standard solutions
79
properties of a good primary standard
high purity, low reactivity, non-toxic, not likely to absorb moisture, high equivalent weight
80
how to make a standard solution
1. Weigh the primary standard
2. Dissolve primary standard in a small amount of dstileld water in a beaker
3. Pour the contents of the beaker into a volumetric flask
4. Add distilled water to the flask up to calibration point, use graduated pipette deliver the final amount
81
electrolysis
Application of an electric current to decompose a compoun
chemical reactin not physical change
e.g. electric current applied to water, gases collect to anode or cathodes
82
percentage compisition formula
mass of the elements in 1 mol of compound
____________________________________
molar mas of the compound
| x100
83
# conversions between units
1g= ?mg
1mg= ?ug
1g= ?ug
1ppm = ?ug/g = ?mg/kg
1ppb= ?ug/kg
1. 10 ^3
2. 10 ^3
3. 10 ^6
4. 1 = 1
5. 1
84
%(w/w)
percentage by mass
describes the mass of solute in greams per 100 g of solution
85
%(w/v)
percentage mass by volume
dercibes the mass of solute in grams per 100ml of solution
86
%(v/v)
percentage by volume
describes the volume of solute in mL per 100ml of solution
87
ppm
grams per million
mg/kg
mg/L
88
ppb
grams per billion
ug/kg
ug/L
89
Dilution
changing concetration by adding water to the solutino
C1V1=C2V2
90
Steps to calculating concentration of a standard solution
| prepped by a priimary solution
1. Determine mm of primary solution
2. Use mm and mass of primary solution to determine moles dissolved in vol flask
3. Use conc formula with n of dissolved and volume of flask
91
reactivity with water
| trends
how readily a element will react with water
how radily a metal atom will release its outer shell eletrons
how reaily a non-metal atom will accept an electron
down a group--> increases for metals, decreases for non-metals
across period--> decreases for metals, increases for non-metals, noble gases in G8 are unreactive
92
properties of metals
lustrous
good heat and electricity conducters
malleable (can be shaped)
ductile (can be drawn into wire)
93
properties of ionic compounds
brittle, hard (resistant to scratching)
high mp
94
Validity
1. Aim
2. Constant variables
3. Equipment apporiaye for less error
4. Range suitable for trend
| ACER
95
Reliability
1. Repeated
2. Outliers
3. Consistent results
3. Averaged
| ROCA
96
Accuracy
1. Scale sufficent
2. Equipment correct
3. Recorded accurately
4. Close to theoritical values
| SERC
97
Indicators of a chemical reaction
bubbles
colour change
change in energy (temp)
appearance of solid (precipitation)
Dissapearance of solid (not from dissolving)
new substance --> guaratees reaction
98
exothermic reaction
| do reactancts or products have mroe energy, caused by
reactants have more energy than the products
energy is released from bonds being formed and goes into the surroundings, usually causing the temperature to rise
99
endothermic reaction
| reactants or products have mroe energy
energy is taken from the surroundings
the reactants have less energy than the products
energy is being used to break bonds, endothermic reactions usually cause the temperature to drop
e.g. decomposition
100
sythesis reactions
| equation in terms of A & B, endo or exo
(A + B → AB)
exothermic (energy given off when bonds broken)
101
displacement reactons
| equation in terms of A-D, features
(A + BC → AC + B or AB + CD → AD + CB) swapping of ions when two salt solutions are mixed
102
precipitation reactions
| equation
(Soluble Salt A (aq) + Soluble Salt B (aq) → Precipitate (s) + Soluble Salt C (aq))
103
decomposition reactions
| equation in terms of A&B, exaples of use
(AB → A + B)
e.g. used in smelting metal ores to separate the pure metal from the ores
e.g. electrolysis of water (creating hydrogen and oxygen)
usually endothermic --> require energy to break bonds
104
Rules for decomposition
Binary compounds (with only 2 different elements) --> elements
Carbonates ---> oxide and carbon dioxide
Chlorates (ClO3) --> binary salt and oxygen
105
Types of decomposition reactions
| 3
thermal through application of heat (endothermic)
Electrolytic through eletric current in aq solution of compound (cells used)
Photo decomposition through light energy/photons
106
acid + base =
| type of reaction
salt + water
neutralisation reaction
107
acid + metal =
| features
salt + hydrogren gas
some metals react more rapidly
Some metals require heat to begin
Gold will not react with weaker acids
108
Metal carbonate + acid=
| or bicarbonate
salt + carbon dioxide + water
109
metal oxide + acid=
salt + water
110
Combustion reactions
Incomplete
Complete
| Write equations of...
Hydrocarbon + Oxygen → Carbon Monoxide + Carbon + Water
Hydrocarbon + Oxygen → Carbon Dioxide + Water
111
# Solubility rules
NAG SAG
PMS
| Always soluble, exceptions (insoluable)
Nitrates
Acetates
Group 1
Sulfates
Ammonium
Group 17
| Pb, Mecury, Silver
112
What elements are in Group 1
Li, Na, K, Rb
113
What elements are in group 17
F, Cl, Br, I
114
Cycads
| Definiton, importance to aboriginals
Type of palm that commonly grows in northern, north eastern Aus
Traditional food source for Aboriginal and Torres Strait Islander Peoples for 1000s years, despite being poisioous
115
Processes of detoxyfying cycads
1. Cook seeds in fire --> denature toxic compounds, break bonds between molecules, remoing ability to disrupt liver and neurological functions, decompose toxins then shorter leaching time
2. Soak in coarse mesh bags in running water for few days (physical) --> dissolve compounds into water, only negliible amount of toxic compound remains (hydrolozed)
3. Immersed in container of water for days --> fermentation, chemical reaction, destroys toxins
116
Collision Theory
For a reation between two particles to occur, the aprticles must collide and the collision must be effective
Enough energy, corret orientation
117
# Reactions of
Metals with oxygen
| Which elements
Na, Li, K spontaneously ignite,
Mg reacts brightly when heated,
Al, Zn, Fe, Nickel burn in pure oxygen if finely divided,
Sn, Pb, Cu, Hg oxidise if heated in pure oxygen,
Ag, Au, Pt do not react
118
# Reactions of
Metals with water
| Which elements
K, Na, Ca react with cold water,
Mg reacts with hot water,
Al, Zn, Fe, Nickel react with steam,
Sn, Pb, Cu, Hg, Ag, Au, Pt do not react
119
# Reactions of
Metal with acids
| Which elements
K, Na, Ca, Mg, Al, Zn, Fe, Nickel react with dilute acid,
Pb reacts with warm dilute acid,
Sn, Cu react with hot concentrated acids to form a salt and a gas other than hydrogen
120
OIL RIG
Oxidation --> lose
Reduction --> gain
121
RED CAT
ANOX
Reduction --> cathode
Oxidation --> anode
122
Oxidation
| equation example
Zn → Zn2+ + 2e-
123
Reduction
| equation example
Cu2+ + 2e- → Cu
124
Oxidising agent
| gain or lose electrions, reduced or oxidised in reaction
the atom that is used when oxidising the other - it gains electrons and is the one being reduced in a chemical reaction
125
Reducing agent
| gain or lose electrions, reduced or oxidised in reaction
the atom that is used when reducing the other - it loses electrons and is the one being oxidised
126
Standard reduction potentials
The table of standard reduction potentials is a table outlining the electric energy potential (voltage) of various half equations.
127
Features of standard reduction potentials
| +-voltage,
positive voltage --> amount fo energy release in spontaneous reaction
negative voltage --> amount of energy provided per mole of reatant for the reaction to occur
values obtained under STC
measured against the hydrogen standard half-cell (which has a potential of 0.00V)
128
Galvanic cell
| contains
two half cells - made up of an solid metal/carbon electrode submerged in an electrolyte (an ion soup that can conduct electricity) - this electrolyte is often a salt solution, such as zinc sulfate or copper sulfate, but can be a paste sometimes.
129
salt bridge
| purpose, made of
allows ions to pass between the cells
a strip of folded filter paper, soaked in 1 mol/L Potassium Nitrate (used because it is relatively inert).
--> the KNO3 ions move to the solutions and neatralise
balance out the charges in each solution - the Potassium cations move to the excessively negative side, and the Nitrate anions move to the excessively positive side
130
Ways to increase rate of reaction
| 5
Increasing temp --> more kinetic energy for collisions, particles faster
Increasing concentration --> more reactant in small space
Increase SA --> more exposed area
Catayst --> decreases activation energy
Increasing pressure --> pushes particles closer together (done by decreasing volume, concetration goes up)
131
Activation energy
| two main purposes
the minimum amount of energy that is required for a set of reactants to begin
1. Exisiting bonds must be broken
2. Reactant molecule must collide at high enough speeds
132
Enthalpy
| equation of chnage in enthaply
energy content of a system
-q
____
n
133
Hess's law
the total enthalpy change for a chemical reaction does not depend on the pathway that it takes - it only depends on the initial and final states.
134
energy profile diagram
epresentations of the energy (or enthalpy) level of the reaction as the reaction progresses.
135
# Enthalpy
Exothermic reactions
| energy in products and reactants
Energy of Products < Energy of Reactants
ΔH < O
136
# Enthaply
Endothermic reactions
| energy in products, reactants
Energy of Products > Energy of Reactants
ΔH > O
137
When bonds are broken, energy is
gained
endo
138
When bonds are formed energy is
released
exo
