Glossary a-e Flashcards
1
Q
absorbance
A
the ability of a substance to absorb a certain wavelength of light
2
Q
absorption line
A
The black lines found in a continuous spectrum of light
3
Q
accuracy
A
how close to the real value a measurement is
4
Q
acid (Arrhenius)
A
a substance that can make hydrogen ions in solution
5
Q
acid (Bronsted-Lowry)
A
a substance that can donate a hydrogen ion (proton)
6
Q
acid - base reaction
A
- when and acid reacts with a base.
* may be called Neutralization when in correct proportion.
7
Q
acid rain
A
rainwater that reacted with acidic gases in the atmosphere to make water with a pH of less than 5.5
8
Q
acidic solution
A
a solution which has more hydrogen ions than hydroxide ions.
pH is < 7
9
Q
acidity
A
the concentration of H+ ions in a solution.
10
Q
What scale measured the acidity of a solution?
A
pH scale
11
Q
activation energy
A
the minimum energy the reactants require for the reaction to occur.
12
Q
What is the symbol for activation energy?
A
Ea.
13
Q
What is the activation energy needed for?
A
To break the bonds between atoms in the reactants
14
Q
active site
A
the specific part of an enzyme molecule where the reactant can interact
15
Q
addition reaction
A
a reaction in which a molecule binds to an unsaturated hydrocarbon (alkene, alkyne) to form a single carbon bond.
16
Q
How many products are formed in an addition reaction?
A
1
17
Q
adsorption
A
when a substance sticks to the surface of a liquid or a solid
18
Q
alkali
A
a soluble base
19
Q
alkali metal
A
a group 1 metal.
20
Q
alkane
A
a saturated hydrocarbon with all single bonds
21
Q
What is the general formula for a straight alkane
A
Cn H(2n+2)
22
Q
alkene
A
an unsaturated hydrocarbon with a double bond between carbons.
23
Q
alkyl group
A
a hyrdocarbon group on main carbon chain
24
Q
alkyne
A
an unsaturated hydrocarbon with a triple bond between .carbons.
25
allotrope
different forms of the same element in which the atoms are bonded in different ways
26
Allotropes of carbon
graphite, diamond
27
Allotropes of oxygen
oxygen gas, ozone gas.
28
alloy
a mixture of a metal an another substance like C or another metal/s.
29
An alloy of copper and tin
bronze
30
An alloy of copper and zinc
brass
31
An alloy of iron and carbon
steel
32
alpha particle
a positively charged particle in radiation, similar to a helium nucleus
33
amorphous
a substance with no consistant structure
34
anion
a negatively charged ion
35
annealing
heating a metal to a moderate temperature and letting it cool slowly. This makes the metal softer and more ductile.
36
What effect does annealing have on a metal?
It makes it softer and more ductile.
37
aqueous (aq)
A substance is dissolved in water.
| i.e. water is the solvent.
38
Arrhenius model - acid
It defines an acid as a substance that ionizes in water to produce hydrogen ions (H+) or protons.
39
Arrhenius model - base
It defines a base as a substance that dissociates in water to form hydroxide OH- ions
40
artesian basin
an underground area of porous rock that stores water.
41
asymmetrical molecule
a molecule in which the polar bonds are unevenly distributed.
42
asymmetrical molecule 2
| dipoles
the bond dipoles do not cancel and and overall dipole is created.
43
atom
The basic building block of matter.
| Smallest particle of an element.
44
What particles make up an atom?
Made of protons and neutrons in the nucleus.
| Surrounded by electrons in shells.
45
atomic absorption spectroscopy (AAS)
A technique that uses light absorption to measure the amount of metal in a sample.
46
atomic number
The number of protons in the nucleus of an atom.
47
What is the symbol of the atomic number?
Z
48
atomic radius
A measurement of the size of an atom, half the distance between adjacent atoms in a molecule
49
atomic theory of matter
states all matter is made up of atoms.
| Atoms are indivisible and elements are made of identical atoms.
50
Avogadro's Law
At the same temperature and pressure equal volumes of all gases contain equal numbers of particles.
51
Avogadro's number
the number of particles in a mole.
| 6.023 x 10 23
52
bar
unit of pressure
53
base (Arrhenius)
a substance capable of producing hydroxide ions.
54
base (Bronsted-Lowry)
a substance capable of accepting a proton.
55
a basic solution
an aqueous solution with more hydroxide ions than hydrogen ions.
56
What is the pH of a basic solution?
pH is greater than 7
57
bias
values skewed in one direction from the true value.
| e.g. too high or too low.
58
biodegradable
capable of being broken down by bacteria
59
biofuel
fuel made from plants such as grains, sugar or vegetable wastes and oils.
60
bohr diagram
a simple diagram that shows the arrangement of electrons around the nucleus.
61
Bohr Model of the Atom
a theory of the atom by Niels Bohr where electrons occupy fixed, circular orbits.
62
bore water
water that comes from underground
63
brittle
shatters when given a sharp tap.
64
buckyball
a ball like structure of carbon atoms.
65
calibrate
to check the scale of an instrument
66
calibration curve
a graph of two variables that can be used to determine the true value of one of the variables
67
carbon-12
the isotopes of carbon that has a mass number of 12,
| 6 protons and 6 neutrons.
68
What is carbon - 12 used to standardize?
one twelfth of the mass of a carbon -12 atom is used to calculate the mass of other atoms.
It makes one atomic mass unit.
69
carbon nanotube
a tube shaped nanoparticle made of carbon atoms
70
catalyst
a substance that increases the rate of a reaction but is not consumed in the reaction.
71
catalysis
the increase in the rate of a reaction due to the presence of a catalyst
72
How does a catalyst work?
By offering a lower energy pathway with a lower activation energy.
73
cation
a positively charged ion
74
centrifugation
a physical separation technique which uses rapid rotation
75
ceramic
material made by the firing of clay.
76
chemical energy
form of energy stored in the chemical bonds between atoms and molecules.
77
What makes chemical energy?
electrostatic forces of repulsion and attraction between the protons and electrons, movement of electrons, rotation and vibration around bonds
78
chemical formula
a representation of a substance using symbols of the elements and showing the ratio between them
79
chemical symbol
A symbolic representation of an element with one or two letters (usually). The first is a capital.
80
chemiluminescence
the light emitted by a chemical reaction (does not produce a significant amount of heat)
81
chlorination
adding chlorine to drinking water to purify it.
82
chromatography
a way of separating a mixture with a moving phase (solvent) over a stationary phase (paper).
83
collision theory
a theoretical model that accounts for the rates of chemical reactions in terms of collisions between particles in a chemical reaction.
84
colloid
a mixture in which very small particles are spread throughout a liquid, solid or gas.
85
how big are the particles in a colloid?
bigger than a molecule but small enough not to settle on standing
86
column chromatography
chromatography technique in which the stationary phase is a column
87
combustion
a rapid reaction with oxygen with the release of a large amount of heat.
88
another name for combustion
burning
89
complete combustion
only products of burning are carbon dioxide and water
90
incomplete combustion
burning leaves other products like carbon and carbon monoxide as well as carbon dioxide and water
91
components
chemicals in a mixture
92
composite material
made up of two or more materials with different properties
93
compounds
a substance made up of two or more types of atoms in a fixed ratio
94
concentrated solution
a solution with a relatively high ratio of solute to solvent
95
concentration
a measure of how much solute is dissolved in a specific volume of solvent ( mole per litre)
96
condensed structural formula
a simple representation of the structural formula of an organic molecule. CH3 .CH3
97
conductivity
permitting the flow of electric charges
98
conductor
an object or type of material that can let electricity pass through
99
control experiment
an experiment carried out in which the independent variable is NOT changed
100
controlled variable
a variable that is kept constant
101
core charge or effective nuclear charge
the effective nuclear charge experienced by the outer shell electrons in an atom.
It indicates the attractive forces felt by the valence electrons.
102
covalent bond
the force of attraction formed when one or more pairs of electrons are shared between two nucleii
103
covalent layer lattice
an arrangement of atoms in a lattice in which there are strong covalent bonds between the atoms that have formed in a layer
104
covalent network lattice
an arrangement of atoms in a lattice in which there are strong covalent bonds between the atoms in all three dimensions
105
cracking
a chemical process during which carbon-carbon bonds in alkanes are broken to form smaller molecules and some unsaturated molecules.
106
credible
reliable and can be backed up with evidence;
| a credible source provides information that one can believe to be true.
107
crude oil
a mixture of hydrocarbons that originates from the remains of prehistoric marine micro-organisms.
These have been broken down by heat and pressure over millions of years.
108
crystal
a solid made up of atoms or molecules arranged in a repeating 3D pattern.
109
crystal lattice
the symmetrical 3D arrangement of atoms or ions inside a crystal.
110
crystallisation
the process in which solid crystals are deposited when the concentration of a solute in a solution increases past the point of saturation.
111
crystallise
form solid crystals.
112
decantation
a separation process in which a layer of liquid is separated from the solid that has settled at the bottom of the liquid.
113
decomposition
a reaction in which a compound is broken down into smaller parts.
114
delocalise
spread out
115
delocalised electron
an electron that is not restricted to the region between two atoms.
116
density
mass per unit volume kg/m-3 or g/cm-3 or g/mL
117
dependent variable
the variable that is measured or observed to determine the effect of changes in the independent variable
118
desalinated seawater
fresh water made by removing salt from sea water
119
desalination
the removal of salts from seawater to obtain fresh water
120
desorption
the breaking of the attraction between a substance and the surface to which the substance is adsorbed.
121
diamond
a form of pure carbon that is hardest naturally occurring substance
122
diatomic molecule
a molecule formed from two atoms only.
123
diffusion
all the gases in a gas mixture spread to fill the available space
124
dilute solution
a solution that has a relatively low ratio of solute to solvent.
125
dilution
the addition of a solvent to a solution to reduce its concentration.
126
dipole
the separation of areas of positive and negative charge in a molecule.
127
dipole-dipole force
a form of intermolecular force that occurs between polar molecules.
128
diprotic acid
an acid that can ionise in water to give 2 hydrogen ions.
129
discrete
a separate or particle
130
dispersion forces
force of attraction between molecules due to temporary dipoles induced in the molecules.
131
temporary dipoles
result of fluctuations (quick changes) in the electron density ( where the electrons are at any one time)
132
dissociate
break apart
133
dissociation
process in which molecules or ionic compound separate into atoms or ions.
134
dissolution
the process of dissolving a solute in a solvent to form a solution.
135
dissolve
to incorporate (mix in) a solid or gas into a liquid to form a solution.
136
distillation
the process of separating a solution by evaporating, condensing and collecting the component of the solution with the lowest boiling point.
e.g. in a mixture of water and alcohol, the alcohol will evaporate off first.
137
double covalent bond
a covalent bond in which 4 electrons are shared
138
ductile
able to be drawn into a wire.
139
elastic collision
collision between particles where kinetic energy is conserved.
140
electrical conductivity
the degree to which a specified material or solution conducts an electric current.
141
electrolyte
a solution or molten substance that conducts electricity by means of the movement of ions.
142
electromagnetic radiation
a form of energy that moves through space.
| e.g. vis light, radio waves, X rays.
143
electromagnetic spectrum
all possible frequencies of electromagnetic radiation shown in order of their wavelength or frequencies.
144
electron
a negatively charged, subatomic particle that occupies the region around the nucleus of an atom
145
subatomic particle
a particle that makes up an atom.
| e.g. electron, neutron, proton.
146
electron configuration
means of representing the number of electrons in each shell
147
electron density
the concentration of electrons that usually refer to the areas around an atom or molecule.
148
electron dot diagram/Lewis structure
a representation of the electron arrangement in a molecule in which the outer-shell electrons are represented by dots or crosses.
149
electron shell
a fixed energy level that corresponds to a circular orbit of the electrons.
150
electron transfer diagram
a diagram that shows how electrons move from a metal atom to a non-metal to form an ion.
151
electronegativity
the ability of an atom to attract electrons in a covalent bond toward itself.
152
electrostatic attraction
the force of attraction between a positively charged particle and a negatively charged particle
153
element
a substance made up of atoms with the same atomic number.
154
elemental analysis
a process that determines the mass of each element in a sample of a compound.
155
eluent
the solvent that carries the components and passes through a chromatography column
156
emission spectrum
A spectrum produced when an element is excited by heat or radiation. It appears as distinct lines characteristic of the element
157
empirical formula
a formula that shows the simplest whole number ratio of the elements in a compound.
e.g C3H6 = CH2
158
endothermic
a reaction that absorbs energy from the surroundings
| ^H is positive.
159
energy content
the chemical energy of a substance
160
energy level
One of the different shells of an atom in which an electron can be found
161
energy profile diagram
The energy changes that occur during the course of a reaction
162
enthalpy
heat content
The sum of the chemical potential and kinetic energies in a substance.
Symbol ^H
163
enthalpy change
The difference in the total enthalpy of the products and the total enthalpy of the reactants
^H
Also known as heat of reaction
164
enzyme
biological catalyst
165
excess reactant
a reactant that is not completely consumed in a chemical reaction
166
excited state
a term used t describe an atom in which electrons occupy higher energy levels than the lowest possible ones
167
exothermic
a reaction that releases energy into the surroundings.
| ^H is negative
