Enthalpy changes bundle OCR AS Chemistry

This bundle is ideal for classroom or home learning and covers all of the OCR A level chemistry specification section 3.2.1 − enthalpy changes. The energetics topics covered are enthalpy changes, experimental determination of enthalpy changes, bond enthalpies and Hess’ Law. Each topic includes a fully interactive PowerPoint including starter, group activities, questions and plenary along with a worksheet. Answers to all exercises are provided. Some of the resources include a PowerPoint quiz.

This bundle is part of a series covering the OCR AS Chemistry specification and relates to the following section:
Module 3 – Periodic table and energy / Part 2 – Physical chemistry / 3.2.1 Enthalpy changes

Content covered:

Enthalpy changes
• What is enthalpy
• Law of conservation of energy
• Enthalpy change
• Enthalpy profile diagrams
• System and surroundings
• Exothermic and endothermic reactions and examples
• Activation energy
• Standard enthalpy changes
• Standard conditions
• Definitions of enthalpy changes
• Simple calculations involving enthalpy changes

Experimental determination of enthalpy changes
• Energy exchange with the surroundings - heat loss in a chemical system = heat gain by surroundings
• Temperature scales
• Determining enthalpy changes using calorimetry
• Calculations involving q = mc∆T .
• Determining enthalpy changes in solution
• Determining enthalpy of combustion
• Errors associated with calorimetry experiments and how to minimise them
• Cooling curves and how to find the temperature rise
• Thermometric titration

Bond enthalpies
• Making covalent bonds (exothermic) and breaking covalent bonds (endothermic)
• Overall enthalpy change linked to relative enthalpies of breaking and making bonds – enthalpy profile diagram
• Average bond enthalpies and why they differ from actual bond enthalpies
• Factors affecting average bond enthalpies
• Calculations involving bond enthalpies
• Limitations of bond enthalpy calculations
• Plenary discussion about why there is a constant increase in the enthalpy change of combustion of alcohols for each CH2 group added

Hess’ Law
• Hess’ Law
• Indirect determination of enthalpy changes
• Enthalpy cycles
• Calculating enthalpy changes from enthalpy changes of combustion
• Calculating enthalpy changes from enthalpy changes of formation
• Summary of types of enthalpy calculation
• Calculating enthalpy changes from unfamiliar enthalpy cycles

Links
Next lesson: Topic 29 – Rates of reaction and collision theory (in preparation)
Free resource - standard form, decimal places and significant figures
https://www.tes.com/teaching-resource/resource-12405507