Key words/principles Flashcards
First law of thermodynamics
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.
Second law of thermodynamics
The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time.
Third law of thermodynamics
The third law of thermodynamics states that the entropy of a perfect crystal at absolute zero is exactly equal to zero
What is oxidation?
The loss of electrons
The gain of oxygen atoms
What is reduction?
The gain of electrons
The loss of hydrogen atoms
Define the term ‘isoelectric point’.
The isoelectronic point is the pH at which the amino acid is neutral, i.e. the zwitterion form is dominant.
What is the Bronsted-Lowry definition of an acid?
An acid is a proton (hydrogen ion) donor.
What is the Bronsted-Lowry definition of a base?
A base is a proton (hydrogen ion) acceptor.
What is the standard enthalpy of formation?
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
What is the standard enthalpy of reaction?
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.
What is the standard enthalpy of combustion?
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.
List the standard conditions
298 K (25°C)
a pressure of 1 bar (100 kPa).
where solutions are involved, a concentration of 1 mol dm-3
Define the term ‘isomer’
each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.
Define the term ‘stereoisomer’
each of two or more compounds differing only in the spatial arrangement of their atoms.
Define the term ‘enantimer’
each of a pair of molecules that are mirror images of each other.
Define the term ‘diastereomer’
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.
What are stereocenters?
A stereocenter is an atom, typically carbon, that has four attachments that are different from each other.
In chemistry, what are spontaneous reactions?
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.
Define the term ‘mass number’
Number of protons + neutrons
Standard temperature and pressure (STP)
0°C
100,000 Pascals (=100 kilopascals)
What is the volume of 1 mole of any gas at STP?
22.4 litres
=22.4 dm3
Absolute zero
The temperature at which all movement of all particles stop –> 0 K
