3.2-Physical Chemistry Flashcards
What is the definition of enthalpy change?
The heat energy transferred in a reaction at constant pressure. The units are kJmol^-1
What are the two main standard conditions?
100 kPa and 298 Kelvin
State two examples of exothermic reactions.
The combustion of a fuel like methane
The oxidation of carbohydrates, such as glucose in respiration
What are 2 examples of endothermic reactions?
The thermal decomposition of calcium carbonate
Photosynthesis
Where can you find enthalpy change values?
In data books or by experimental methods
What is the definition of the standard enthalpy change of reaction?
The enthalpy change when the reaction occurs in the molar quantities shown in the chemical reaction, under standard conditions
What is the definition of the standard enthalpy change of formation?
The enthalpy change when one mole of a compound is formed from its elements in their states,under standard condition
What is the definition of the standard enthalpy change of combustion?
The enthalpy change when one mole of the substance is completely burnt in oxygen, under standard conditions
What is the definition of the standard enthalpy change of neutralisation?
The enthalpy change when an acid and an alkali react together, under standard conditions, to form one mole of water
What type of reaction is Breaking Bonds?
Endothermic
What type of reaction is making bonds?
Exothermic
What is the equation for calculating enthalpy change?
E=mcT
What is the specific heat capacity of water?
4.18 Jg^-1 K^-1
