Key words/principles

Question 1

First law of thermodynamics

Answer 1

The First Law of Thermodynamics states that heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy. This means that heat energy cannot be created or destroyed.

Question 2

Second law of thermodynamics

Answer 2

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time.

Question 3

Third law of thermodynamics

Answer 3

The third law of thermodynamics states that the entropy of a perfect crystal at absolute zero is exactly equal to zero

Question 4

What is oxidation?

Answer 4

The loss of electrons

The gain of oxygen atoms

Question 5

What is reduction?

Answer 5

The gain of electrons

The loss of hydrogen atoms

Question 6

Define the term ‘isoelectric point’.

Answer 6

The isoelectronic point is the pH at which the amino acid is neutral, i.e. the zwitterion form is dominant.

Question 7

What is the Bronsted-Lowry definition of an acid?

Answer 7

An acid is a proton (hydrogen ion) donor.

Question 8

What is the Bronsted-Lowry definition of a base?

Answer 8

A base is a proton (hydrogen ion) acceptor.

Question 9

What is the standard enthalpy of formation?

Answer 9

The standard enthalpy of formation of a compound is the change of enthalpy during the formation of 1 mole of the substance from its constituent elements, with all substances in their standard states

Question 10

What is the standard enthalpy of reaction?

Answer 10

The standard enthalpy of reaction is the enthalpy change that occurs in a system when matter is transformed by a given chemical reaction, when all reactants and products are in their standard states.

Question 11

What is the standard enthalpy of combustion?

Answer 11

The standard enthalpy change of combustion of a compound is the enthalpy change which occurs when one mole of the compound is burned completely in oxygen under standard conditions.

Question 12

List the standard conditions

Answer 12

298 K (25°C)
a pressure of 1 bar (100 kPa).
where solutions are involved, a concentration of 1 mol dm-3

Question 13

Define the term ‘isomer’

Answer 13

each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.

Question 14

Define the term ‘stereoisomer’

Answer 14

each of two or more compounds differing only in the spatial arrangement of their atoms.

Question 15

Define the term ‘enantimer’

Answer 15

each of a pair of molecules that are mirror images of each other.

Question 16

Define the term ‘diastereomer’

Answer 16

Diastereomerism occurs when two or more stereoisomers of a compound have different configurations at one or more of the equivalent stereocenters and are not mirror images of each other.

Question 17

What are stereocenters?

Answer 17

A stereocenter is an atom, typically carbon, that has four attachments that are different from each other.

Question 18

In chemistry, what are spontaneous reactions?

Answer 18

A spontaneous processes is one that occurs without the addition of external energy. It may take place quickly or slowly, because spontaneity is not related to kinetics or reaction rate.

Question 19

Define the term ‘mass number’

Answer 19

Number of protons + neutrons

Question 20

Standard temperature and pressure (STP)

Answer 20

0°C

100,000 Pascals (=100 kilopascals)

Question 21

What is the volume of 1 mole of any gas at STP?

Answer 21

22.4 litres

=22.4 dm3

Question 22

Absolute zero

Answer 22

The temperature at which all movement of all particles stop –> 0 K