Definitions

Question 1

What is the Principle of the Mass Spectrometer

Answer 1

To separate and deflect
Positively charged Ions
According to their atomic masses
When moving in a magnetic field

Question 2

Energy Level

Answer 2

Orbital which electrons of equal energy can occupy

Question 3

Visible Lines in Hydrogen Emission Spectrum

Answer 3

Balmer Series

Question 4

Atomic Radius

Answer 4

Half the distance between the two nuclei of atoms of the same element in a single covalent bond

Question 5

First Ionisation Energy

Answer 5

The minimum energy required
To completely remove
The most loosely bound electron
Of a neutral gaseous atom
In it’s ground state

Question 6

Electronegativity

Answer 6

The relative force of attraction an atom has for the shared pair of electrons in a covalent bond

Question 7

Isotopes Definition

Answer 7

Atoms of the same element which differ by atomic mass (number of neutrons in nucleus)

Question 8

Radio Isotope Definition

Answer 8

Isotope atom with an unstable nucleus

Question 9

Half-Life

Answer 9

Time taken for half of the sample to decay

Question 10

What happens to an atom after alpha decay

Answer 10

Looses a ‘He’ atom

Question 11

Radioactivity

Answer 11

Spontaneous decay of a nucleus, releasing radiation

Question 12

Mole / Avogadro’s Constant

Answer 12

A mole of a substance is the amount of a substance that contains 6x10^23 particles of that substance

Question 13

Chemical Equilibrium

Answer 13

A state of chemical balance where the rate of the forward reaction equals the rate of the reverse reaction

Question 14

Dynamic Reaction

Answer 14

A reaction where the forward and backwards reactions are both occurring continuously

Question 15

Le Chatelier’s Principle

Answer 15

If a reaction at equilibrium is put under stress, the equilibrium will shift to relieve the stress

Question 16

Avogadro’s Law

Answer 16

Equal volumes of gases at the same temperature and pressure have equal number of moles

Question 17

Charles’s Law

Answer 17

For a gas of a definite mass, at a constant pressure, the volume of the gas is directly proportional to the Kelvin temperature

Question 18

Boyle’s Law

Answer 18

For a gas of a definite mass at a constant temperature, the volume of a given mass of any gas is inversely proportional to its pressure

Question 19

Gay-Lussac’s Law of Combining Values

Answer 19

In a reaction between gases the volumes of the reacting gases and the volumes of any gaseous products are in the ratio of small whole numbers provided the volumes are measured at the same temperature and pressure

Question 20

Kinetic Theory of (Ideal) Gases

Answer 20

1. Volume is negligible compared to space it occupies
2. No attractive or repulsive forces between particles
3. Particles are in constant random motion and are constantly hitting walls of container and themselves
4. Average kinetic energy of the particles is or optional to Kelvin temperature
5. All collisions are perfectly elastic

Question 21

Real Gas vs Ideal Gas

Answer 21

Molecules have volume, when gas it at high pressure / low volume it is not ok to say volume is negligible

Intermolecular forces are present

Collisions are not perfectly elastic

Question 22

Ideal Gas

Answer 22

An ideal gas is one which obeys all the gas laws under all conditions of temperature and pressure

Question 23

When do real gases behave most like ideal gases?

Answer 23

High Temperatures

Low Pressures / High Volumes

Question 24

Arrhenius Acids / Bases

Answer 24

Dissociates in water to form H+ / OH-

Question 25

What are Cathode Rays

Answer 25

Streams of negatively charged particles called electrons that travel in a straight line from the cathode to the anode

Question 26

What is an energy level

Answer 26

The fixed energy value that an electron in an atom may have

Question 27

What is an atoms ground state

Answer 27

The state in which the electrons occupy the lowest available energy levels

Question 28

What is an atoms excited state

Answer 28

When the electrons occupy higher energy levels than those available in the ground state

Question 29

Heisenburgs Uncertainty Principle

Answer 29

It is impossible to detect both the position and then velocity of an electron in an atomic orbital at any one time

Question 30

What is a sub level

Answer 30

A subdivision of a main energy level and consists of one or more orbitals of the same energy

Question 31

What is an element

Answer 31

A substance that cannot be split into simple substances by chemical means

Question 32

Dobereiner’s Triads

Answer 32

A group of three elements with similar chemical properties in which the atomic weight of the middle element is approx. equal to the average of the other two

Question 33

Newlands Octaves

Answer 33

Arrangements of elements in which the first and the eight element, counting from a particular element have similar properties

Question 34

Mendeleev’s periodic law

Answer 34

When elements are arranged in order of increasing atomic weight the properties of the elements recur periodically

Question 35

Atomic number of an element

Answer 35

The number of protons in the nucleus’s of an atom of the element

Question 36

Modern Periodic Law

Answer 36

When elements are arranged in order of increasing atomic number, the properties of the elements recur periodically

Question 37

Mass number

Answer 37

Sum of protons and neutrons

Question 38

Isotopes

Answer 38

Atoms of the same element which have different mass numbers did to having different numbers of neutrons in their nuclei

Question 39

Relative atomic mass

Answer 39

The average mass numbers of all the isotopes of an element when taking their abundances into account expressed on a scale where the isotope of a carbon-12 atom has an atomic mass of 12

Question 40

What is a compound

Answer 40

A substance that is made up of two or more different elements combined together chemically

Question 41

What is the Octet Rule

Answer 41

When bonding occurs, atoms tend to reach an electron arrangement with eight electrons in the outermost energy level

Question 42

What is an Ion

Answer 42

A charged atom or group of atoms Cations = positively charged Anions = negatively charged

Question 43

What is an ionic bond

Answer 43

The force of attraction between oppositely-charged ions in a compound. Ionic bonds are always formed by the complete transfer of electrons from one atom to another

Question 44

What is a transition metal

Answer 44

A metal that forms at least one ion with a partially-filled d sublevel

Question 45

What is a molecule

Answer 45

A group of atoms joined together. It is the smallest particle of an element or compound that can exist independently

Question 46

What is the valency of an element

Answer 46

The number of atoms of hydrogen or any other monovalent element with which each atom of the element combines

Question 47

What is a polar covalent bond

Answer 47

A bond in which there is unequal sharing of the pair or pairs of electrons This causes one end of the bond to be slightly positive and the other end slightly negative

Question 48

What is a Gas?

Answer 48

A gas is a substance which has no well-defined boundaries but diffuses rapidly to fill any container in which it is placed

Question 49

Equation of State for an Ideal Gas

Answer 49

pV=nRT R = universal gas constant = 8.31