Definitions Flashcards

1
Q

What is a mixture

A

A combination of two or more substances where the substances are not joined or bonded together and no chemical reaction occurs between the substances

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2
Q

What is an element

A

A substance that cannot be broken down into other substances by chemical means

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3
Q

What is a compound

A

A group of two or more atoms, attracted by a relatively strong bond, the atoms are combined in fixed proportions

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4
Q

What is a cation

A

A positive ion formed when a neutral atom loses one or more electrons

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5
Q

What is an anion

A

A negative ion formed when a neutral atom gains one or more electrons

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6
Q

What is a metalloid

A

A element with mostly non-metallic properties, their distinguishing characteristic is that their conductivity increases as their temperature increases

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7
Q

What is diffusion

A

The movement of particles from a high concentration to a low concentration

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8
Q

What is the Brownian motion

A

Random motion of particles suspended in a liquid or gas resulting from their collision with quick atoms or molecule in the liquid or gas

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9
Q

What is a freezing point

A

The temperature at which a liquid changes it’s phase to become a solid

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10
Q

What is a boiling point

A

The point at which a liquids vapour pressure is equal to atmospheric pressure

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11
Q

What is a melting point

A

The point at which a solid changes it’s phase to become a liquid

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12
Q

What is evaporation

A

Process of going from a liquid to a gas

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13
Q

What is sublimination

A

Process of going from a solid to a gas

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14
Q

What is condensation

A

The process of going from a gas to a liquid

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15
Q

What is the kinetic molecular theory

A

All matter is composed of particles which have a certain amount of energy which allows them to move at different speeds depending on the temperature (energy)
. There are spaces between the particles and also attractive forced between particles when they come closer together.

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16
Q

What is latent/transitional heat

A

The heat produced or released during a phase change

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17
Q

What are volatile liquids

A

Liquids that evaporate at room temperature

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18
Q

What is the difference between macroscopic and microscopic properties

A

Macroscopic properties refer to boiling and melting melting points and evaporation. Microscopic refers to what happens in the atom and the molecular structure of sun stances

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19
Q

What is Relative atomic mass

A

The ratio of the average mass of one atom of an element to one twelfth of the mass of atom carbon-12

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20
Q

What is atomic number (Z)

A

Number of protons in an atoms

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21
Q

What is a proton

A

A particle found in the nucleus of an atom, it is positively charged

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22
Q

What is an electron

A

Smallest particle that makes up an atom and is found outside the nucleus, it is negatively charged

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23
Q

What is a neutron

A

A particle found in the nucleus of an atom, it has no electrical charge

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24
Q

What is atomic mass (A)

A

Number of protons and neutrons in the nucleus of an atom

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25
What is an isotope
Atoms of the same element that have the same number of protons (Z), but a different number of neutrons (A) resulting in different atomic masses.
26
What is the Aufbau Principle
Electrons orbiting one or more atoms, fill the lowest available energy levels before filling their higher energy levels.
27
What is Hunds rule
Electrons would rather be in a subshell on their own than share the orbital in the same energy level
28
What is Pauli’s Exculsion principle
Electrons have a property spin and two electrons must have opposite spin in order to share a subshell
29
What is an orbital
Region of space where you are most likely to find electrons
30
What are valence electrons
Electrons that are found int the outermost energy level of an atom that can participate in forming chemical bonds with other atoms
31
What is an atomic radius
The measure of size of the atom (the distance from the centre of the nucleus to the point where the electron cloud ends)
32
What is a group
Vertical columns on the period table
33
What is electron affinity
The amount of energy released when an atom in the gaseous phase gains an electron to form a negative ion
34
What is electronegativity
The measure of the tendency of an atom to attract bonding electrons
35
What is a chemical bond
A Physical process that causes atoms to be attracted to each other and held together in more stable compounds called molecules
36
What is the first ionisation energy
The amount of energy required to remove the first electron from an atom in its gaseous state to form a positive ion
37
What is periodicity
Quality or character of being repeated in intervals
38
What is valency
The number of electrons in the outer shell of an atom which are able to form bonds with other atoms
39
What is molar mass
The mass of one mole of that substance
40
What is a halide
A binary compound of a halogen with another elector group of elements
41
What is an oxide
An ion of oxygen (O2-)
42
What is ionic bonding
A transfer of electrons and subsequent electrostatic attraction
43
What is covalent Bonding
A sharing of at least one pair of electrons by two non-metals
44
What is metallic bonding
Electrostatic attraction between the positively charged atomic nuclei of metal atoms and a sea of delocalised electrons
45
What is a delocalised electron cloud
Electrons that are not at a specific point in a group of atoms
46
What is a molecule
When atoms share electrons, are bonded covalently then the resulting collection of atoms is known as a molecule
47
What is a covalent molecular structure
A crystal lattice that consists of separate molecules
48
What is a covalent network structure
Crystal lattice that consists of giant repeating lattices of covalently bonded atoms
49
Molecular formula
A concise way of expressing information about the atoms that make up a particular covalent molecular compound. Gives the exact number of each type of atom in the molecule
50
What is the empirical formulae
Shows the simplest ratio of atoms in the compound
51
What is physical change
A change that does not alter the chemical nature of the substances, no new chemical substances are formed
52
What is a chemical change
A change in which the chemical nature of the substances involved changes, new chemical substances are formed
53
What is the law of constant proportions
A chemical compound always contains exactly the same proportion of elements by mass
54
What is the law of conservation of mass
The total mass of substances taking part in a chemical reaction is conserved during the reaction
55
What is dissolving
Solid ionic crust and breaking up into ions in H2O
56
What is Dissociation
The process in which ionic compounds separate into smaller ions
57
What is hydration
Where ions become surrounded with water molecules in a water solution
58
What are electrolytes
A substance that contains free ions and behaves as an electrically conductive medium
59
What is a precipitate
A solid that forms in a solution during a chemical reaction
60
What is non polar covalent
The equal sharing of bonding electrons
61
What is polar covalent
The unequal sharing of bonding electrons
62
What is a frame of reference
A reference point combined with a set of directions
63
What is position
A vector quantity that points from the reference point as the origin
64
What is displacement
The change in position of an object
65
What is distance
The length of the path travelled
66
What is speed
The rate of change in distance
67
What is velocity
The rate of change in displacement
68
What is average speed
The total distance covered in the total time (eg you travelled from a to b to c what is the average speed from a to c)
69
What is instantaneous speed
Instantaneous speed is the speed at a particular moment in time
70
What is average velocity
The total displacement per unit time (total distance/ total time) (takes on the direction of the displacement.)
71
What is instantaneous velocity
The velocity at a particular moment in time
72
What is acceleration
The rate of change of velocity
73
What is gravitational potential energy
The energy an object poses due to its position relative to a reference point
73
What is gravitational potential energy
The energy an object poses due to its position relative to a reference point
74
What is Kinetic energy
The energy an object has as a result of the objects motions
75
What is mechanical energy
The sum of gravitational potential energy and kinetic energy at a point
76
What is the law of conservation of energy
The total energy in a system cannot be created or destroyed only transformed from one form to another
77
What is the principle of conservation of mechanical energy
On the absence of air resistance, friction or any external forces, the mechanical energy of an object is constant (Ep + Ek)i = (Ep + Ek)f
78
What is amplitude
The maximum disturbance of a particle from rest/equilibrium position
79
What is constructive interference
When two pulses (waves) meet, resulting in a bigger pulse (wave)
80
What is destructive interference
When two pulses (waves) meet, resulting in a smaller pulse (wave)
81
What is a wave
A periodic , continuous disturbance that consists of a train of pulses
82
What is a transverse wave
A wave where the movement is perpendicular to the direction of the propagation of the wave. Succession of transverse pulses.
83
What is a longitudinal wave
A wave where the particles in the medium move parallel to the direction of the propagation of the wave. Succession of longitudinal pulses
84
What is rare fraction
A region in a longitudinal Wave where particles are furthest apart
85
What is a compression
A region in a longitudinal wave where the particles are closed together
86
What is wavelength
The distance between any two adjacent points that are in phase.
87
What is frequency
The number of successive crests (or troughs) passing a given point in one second
88
What is a period
The time taken for two successive crests (or troughs) to pass a fixed point
89
What is a crest of a wave
The point where the displacement of the medium is at its maximum
90
What is the trough of the wave
The point of the wave where the displacement of the medium is at its minimum
91
What is the wave speed
The distance travelled by the wave per unit time. Product frequency and wavelength of a wave. c = f λ
92
What is ultrasound
Sound with frequencies higher than 20kHz up to about 100kHz
93
What is electromagnetic radiation
Radiation consisting of self-sustaining oscillating electric and magnetic fields at right angles to each other and to the direction of propagation. It does not require supporting medium and travels through space at the speed of light
94
What is the dual nature of electro magnetic radiation
It behaves as a particle and a wave
95
What is a photon
A particle of light with a discrete amount of electromagnetic energy
96
What Is a magnetic field
A region of space where a magnet or ferromagnetic material will experience a non contact force
97
What is the gravitational field
The force acting per unit mass
98
What is gravitational potential energy
The energy an object possesses due to its position relative to a reference point
99
What is kinetic energy
The energy an object has as a result it’s motion
100
What is mechanical energy
The sum of gravitational potential energy and kinetic energy at a point
101
Activation energy
The minimum energy required to start a chemical reaction