Principles of Chemistry Flashcards
(108 cards)
1
Q
arrangement of particles in solid liquid and gas
A
solid - regular arrangement
liquid and gas - randomly arranged
2
Q
movement of of particles in solid liquid and gas
A
solid - vibrate about a fixed position
liquid - move around each other
gas - move quickly in all directions
3
Q
closeness of particles in solid liquid and gas
A
solid - closest
liquid - close
gas - far apart
4
Q
how do solids melt/ lquids boil
A
-heat energy absorbed by particles causes the particles to have more kinetic energy
-causes the particles to vibrate and move more
-melting/boiling happens at a specific temperature (melting/boiling point)
5
Q
at what temperature does water evaporate and where does it happen
A
-up to 100C (boiling points)
-surface of the liquid where high energy particles can escape from the liquid’s surface
6
Q
sublimation
A
when a solid changes directly into a gas
7
Q
desublimation
A
when a gas goes directly to a solid
8
Q
how does condensation happen
A
when a gas cooled its particles lose energy and when they bump into each other they lack the energy to bounce away again, and form a liquid
9
Q
solvent
A
liquid in which a solute dissolves
10
Q
solute
A
the substance which dissolves in a liquid to form a solution
11
Q
solution
A
the mixture formed when a solute is dissolved in a solvent
12
Q
saturated solution
A
a solution with the maximum concentration of solute dissolved in the solvent
13
Q
soluble
A
describes a substance that can dissolve
14
Q
insoluble
A
describes a substance that cannot dissolve
15
Q
solubility meaning
A
measurement of how much of a substance will dissolve in a given volume of a liquid
16
Q
how is solubility of gases affected by temp and pressure
A
-as temperature increases, gases become less soluble
-as pressure increases they become more soluble
17
Q
how is solubility of solids affected by temperature
A
as temperature increases, solids become more soluble
18
Q
solubility graph/curve
A
shows the solubility in g per 100g of water plotted against temperature
19
Q
element
A
substance made of atoms that all contain the same number of protons and cannot be split into anything simpler
20
Q
compound
A
a pure substance made up of two or more elements chemically combined
21
Q
mixture
A
-combination of two or more substances that are not chemically combined
22
Q
pure substance meaning
A
a pure substance consists of a single element of compound which contains no other substances
23
Q
impure substances melting point and boiling point
A
-lower melting point
-higher boiling point
-range of melting and boiling points
24
Q
simple distillation purpose
A
separate a liquid and soluble solid from a solution or a pure liquid from a mixture of liquids
25
simple distillation method
1. heat solution, pure water evaporates producing water vapour which rises through flask
2. vapor passes through condenser, where it cools and condenses, turning into pure liquid
3. pure liquid is collected in a beaker
4. after all liquid is evaporated from the solution, only solid solute is left behind
26
fractional distillation purpose
-used to separate two or more liquids that are miscible with one another
27
fractional distillation method
1. solution is heated to the temperature of the substance with lowest boiling point
2. the substance rises and evaporate first, and vapour will pass through a condenser, turning into a liquid that will be collected in a beaker
3.all substances are evaporated and collected, leaving behind the other components and mixtures
28
filtration
used to separate an undissolved solid from a mixture of the solid and a liquid
29
process of filtration
1. piece of filter paper is placed in a filter funnel above a beaker
2. a mixture of insoluble and liquid is poured into the filter funnel
3. the filter paper will only allow a small liquid particles to pass through as filtrate
4. solid particles are too large to pass through the filter paper so will stay behind as a residue
30
crystalisation
used to separate a dissolved solid from a solution. where the solid is more soluble in hot solvent that in cold
31
crystallisation process
1. solution is heated, allowing the solvent to evaporate, leaving a saturated solution behind
2. test if the solution is saturated by dipping a clean, dry, cold glass rod into the solution. If the solution is saturated, crystals will form on the glass rod
3. saturated solution is allows to cool slowly
4. crystals begin to grow as solids come out of solution due to decreasing solubility
5. the crystals are collected by filtering the solution, they are washed with cold distilled water to remove impurities and are then allowed to dry
32
use of chromatography
-to separate substances that have different solubilities in a solvent
33
how to carry out chromatography
1. pencil line (pencil used as ink is soluble and would run into the chromatogram is drawn on chromatography paper
2.spots of the sample are placed on it
3. paper is lowered into the solvent container, the pencil line above the level of solvent (so samples do not wash into the solvent container)
4. remove paper when solvent almost reaches the top/spots stop moving
5. mark solvent front on paper
6. allow to dry
34
how to determine pure or impure substances on chromatograms.
-pure only producers one spot
-impure produces more than one spot
35
how to identify if a substance is a mixture, and if two substances are identical
-mixture - separates on the paper to show all different components as spots (two or more spots is a mixture)
-identical substances have identical chromatograms
36
Rf value equation
Rf = distance moved by substance/distance moved by solvent
-no units
-is a ratio
-always less than/equal to one
37
atom
smallest particle of an element that contains electron surrounding a nucleus that contains protons and neutrons
38
molecule
a group of two or more atoms chemically bonded with covalent bonds
39
relative mass, and charge of a proton
1, +1
40
relative mass and charge of a neutron
1, 0 (neutral)
41
relative mass and charge of an electron
1/2000, -1
42
atomic number
The number of protons in the nucleus of an atom
43
Mass number
The number of protons and neutrons in the nucleus of an atom
44
Isotope
Atoms of the same element which have the same number of protons but a different number of neutrons
45
Relative atomic mass
The average mass of one atom of an element, taking into account the abundance of all the isotopes for the element.
46
formula for relative atomic mass
Ar = (% isotope A x mass of isotope A) + (% isotope B x mass of isotope B).../100
47
how are elements on the periodic table arranged
-in order of increasing atomic number
-done in a way that element are in columns which other elements which have similar properties
48
period meaning
-horizontal rows that show the number of shells of electrons an atom has and are numbered 1-7
-in electronic configuration it is the number of notations
49
group meaning
-vertical columns that show how many outer electrons each atom has numbered 1-7, with a final group called 0 instead of 8
-in electronic configuration it is the last number, unless it has a full outer shell
50
how does the the energy level of a shell change
further away from the nucleus = more energy
51
how many electrons can each shell have
2, 8, 8, 2
52
how many outer shells can metals and non-metals have
metal: 1-3 outer shell electrons
non-metal: 4-7 outer shell electrons
53
electrical conductivity of metals vs non-metals
metals: good conductor
non-metal: poor conductor
54
type of oxide of metals and non metals
metal: basic oxide
non-metal: acidic oxide (some are neutral)
55
reactivity with acid of metal and non-metal
metal: many react with acids
non-metal - usually do not react with acids
56
physical characteristics of metals
-solid at room temp (except mercury)
-malleable, can be bent and shaped
-(ductile, can be made into wires)
-high melting and boiling po int
57
physical characteristics of non metals
-dull, non-reflective
-different states at room temperature
-flaky and brittle
-low melting and boiling points
58
why do elements in the same group in the periodic table have similar chemical properties
-same number of outer electrons, will react and bond similarly
59
features of noble gases
-non-metals
-monatomic
-colourless and non-flammable gases and rtp
-unreactive and do not form molecules easily
60
why are noble gases unreactive
-they have full outer shells of electrons and are unreactive
61
law of conservation of mass
-allows us to balance chemical equations as no atoms can be lost or created
62
Avogadro constant value
6.02 x 10 to the 23 per atoms per mole
63
equation relating mass, mole and Mr (molar mass)
moles x molar mass = mass
64
reacting mass calculations
look on goodnotes
65
yield meaning
describe the amount of product you get from a reaction
66
why cant 100% yield not be achieved
-reactants may be left behind in equipment
-reaction may be reversible and products continually turn back into reactants
-products may be lost during separation and purification stages
-side reactions can occur where a substance reacts with a gas in the air or an impurity in reactants
-products can be lost during transfer from containers
67
percentage yield equation
% yield = (actual yield/theoretical yield) x 100
68
how to determine toe formula of hydrated copper sulfate, CuSO4.xH20 (. shows water present is water of crystallisation
1. measure mass of evaporating dish
2. add a known mass of hydrated salt (CuSO4)
3. heat over a bunsen burner, stirring until blue salt turns completely white, showing all water has been lost (do not overheat salt as it could decompose)
4. record mass of evaporating dish and its contents
5. subtract initial mass of white salt from mass of hydrated salt
6. do moles calculations
69
molecular formula
formula that shows the number and type of each atom in a molecule
70
empirical formula
shows the simplest whole number ratio of the atoms of each element present in one molecule or formula unit of the compound
71
concentration meaning
the amount of solute there is in a specific volume of the solvent
72
formula relating concentration, number of moles of solute and volume of solution
concentration(mol/dm) = (number of moles of solute)(mol)/(volume of solution)(dm)
73
formula relating volume and amount of gas in moles
volume = 24dm (24k cm) x moles of gas
74
what is an ion
an electrically charged atom or molecule formed by the loss or gain of electrons
75
why does the loss or gain of electrons take place
to obtain a full outer shell of electrons
76
what are cations and anions
anions are negative ions that have gained electrons
cations are positive ions that have lost electrrons
77
charge of ionic compounds
neutral (atoms are charged but the compound is not)
78
how to find the formula of ionic compound
swap the charges of the atoms
79
draw dot and cross dioagrams
-`
80
ionic bond
strong electrostatic force of attraction between oppositely charged ions
81
features of ionic bonds
-high melting points
-giant lattice
82
why do ionic bonds have high melting points
SFE - structure, force of attraction, energy
-giant ionic structure
-lots of strong ionic bonds throughout the structure
-lots of energy is needed to break these bonds
83
conductivity of ionic compounds
only in molten state or in solution
84
why can ionic compounds conduct electricity when molten
-the ions are able to move and carry a charge
85
what are covalent bonds
SEFABSPEAN
-strong electrostatic force of attract between shared pair of electrons and nuclei
86
types of structures that have covalent bonds
-simple molecular
-giant covalent
87
what are shared electrons called in covalent bond
bonding electrons
88
covalent dot and cross
-
89
why does this compound (simple molecular structure) have low melting and boiling point
-this compounds has a simple molecular structure
-it has weak intermolecular forces in between molecules
-little energy energy is needed to break these bonds and melt the compound
90
what are allotropes
different forms of the same element
91
what are allotropes of carbon
buckminster fullerene, diamond, graphite
92
what are fullerenes
-carbon allotrope that consists of molecules that form hollow tubes or spheres
93
uses of fullerene
-trap other molecules by forming around target molecule and capturing it, used for drug delivery systems
-big surface area to trap catalyst molecules on their surface, making them accessible to reactants for catalysis
-some are good lubricants and used in industrial processes
94
how does the melting and boiling point of substances increase as relative molecular mass increases and why
-melting point increases as well
-more electrons in the structure, more intermolecular forces of attraction that need to be overcome when a substance changes state
-more energy is needed to overcome the forces = high boiling point
95
can simple molecular structures conduct electricity and why
No
-no free ions or electrons even in water as there are no ions to carry charge
-are commonly insulators like plastic, rubber and wood
96
features of giant covalent structures
-solids with high melting point
-giant lattice and fixed ratio of atoms in the structure
-non-metal atoms bonded to other non-metal atoms via strong covalent bonds
97
why is diamond hard
-giant covalent structure
-lots of strong covalent bonds throughout the structure, carbon is bonded to 4 other carbon atoms
(hardness of diamonds can be used for cutting tools)
98
why does diamond have a high melting point
-giant covalent structure
-lots of strong covalent bonds throughout the structure between carbon atoms
-lots of energy required to overcome/break these, high melting point
99
structure of graphite
-each carbon atom bonded to three others
-layers of hexagons formed, leaving on free electron per carbon atom
100
why is graphite soft and slippery
-carbon atom bonded to three other carbon atom forming layers
-layers are held together by weak forces between the layers, not covalent bonds.
-layers are free to slide over each other, making it slippery, good as a lubricant
101
why can graphite conduct electricity and heat well
-each carbon atom only forms three bonds, one electron from each carbon atom is delocalised
-delocalised electron are free to move
-free moving electrons = conduct electricity, allow heat to be conducted through the lattice quickly
102
why does graphite have a high melting point
-giant covalent structure
-lots of strong covalent bonds throughout the structure between atoms which need lots of energy to break
103
what are metallic bonds
SEFABPISODE
-strong electrostatic force of attraction between positive ions and sea of delocalised electrons
104
features of metallic bonds
-giant structures of atoms arranged in a regular pattern
-atoms lose their outer electrons and become positively charged ions
-electrons do not belong to specific metal atoms and are 'delocalised', can move freely between the positive metal ions
-
105
why do metals have high boiling points
-
106
why can metals conduct electricity
delocalised electrons available to move and carry charge
107
why are metals malleable (bent into shape without cracking)
-atoms are arranged in layers which can slide over each other when a force is applied
-means they can be hammered into shape
108
electrolysis
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