Lesson Slideshow Section 01
Unit Summary Section 02
Key Concepts
Enthalpy (ΔH), Hess’s Law, Calorimetry, Entropy (ΔS), Gibbs Free Energy (ΔG)
Assessment Objectives
State Hess's Law, Calculate ΔH via calorimetry, Predict reaction spontaneity
Prior Knowledge Needed
Stoichiometry, bond enthalpy, exo/endothermic reactions
IB Syllabus Reference
R1.1, R1.2
Interactive Study Guide
Click here to view the full, detailed topic summary for this unit.
29
Cu
63.546
Video Lesson Section 03
Video Instruction
2 Lessons Available
Calorimetry
Hess Cycles
Practice Quiz Section 04 · Interactive
10
Ne
20.180
Vocabulary Review Section 05
Enthalpy Change ($\Delta H$)
The heat energy change measured under constant pressure.
Exothermic
A reaction that releases heat to the surroundings ($-\Delta H$).
Endothermic
A reaction that absorbs heat from the surroundings ($+\Delta H$).
Specific Heat Capacity
The energy required to raise the temperature of $1\text{g}$ of a substance by $1\text{K}$.
Standard Enthalpy of Formation
The enthalpy change when one mole of a compound is formed from its elements in their standard states.
Bond Enthalpy
The average energy required to break one mole of a specific bond in gaseous molecules.
Hess's Law
The enthalpy change for a reaction is independent of the route taken.
Calorimetry
The experimental technique of measuring heat changes during chemical or physical processes.
Enthalpy of Combustion
Enthalpy change when one mole of a substance is burned completely in oxygen.
Enthalpy of Neutralization
Enthalpy change when an acid and base react to form one mole of water.
Closed System
A system where energy can be exchanged with surroundings but matter cannot.
Activation Energy
The minimum energy required for a collision to result in a reaction.
Surroundings
Everything outside the chemical system being studied (e.g., water in a calorimeter).
26
Fe
55.845
Revision Notes Section 06
79
Au
196.967
Practice Tests Section 07
17
Cl
35.45
Worksheets & Labs Section 08