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A Level Chemistry Enthalpy Change Calculations: Key Concepts and Formulas
This document covers essential concepts for A Level Chemistry enthalpy change calculations, including standard conditions, enthalpy of combustion, and practical calculations.
05/04/2023
189
This page presents a practical example of calculating the enthalpy change of combustion for ethanol.
Example: Given experimental data:
- Mass of water = 400 g
- Temperature change of water = +36.5 °C
- Mass of fuel combusted = 3.75 g
- Molar mass of ethanol = 46.0 g mol⁻¹
The calculation process is demonstrated step-by-step:
This page focuses on the practical determination of enthalpy change of combustion for liquid fuels.
Highlight: The density of water is 1 g cm⁻³, and its specific heat capacity is 4.18 J g⁻¹ K⁻¹.
Steps for determining enthalpy change of combustion:
Example: Calculation for propan-1-ol combustion:
- 1.50 g of propan-1-ol heated 250 cm³ of water by 45°C
- Heat gained by water: Q = 250 × 4.18 × 45 = 47,025 J
The page emphasizes that combustion reactions are exothermic, releasing heat to the surroundings.
This page delves into the specifics of standard conditions and introduces the concept of standard enthalpy change of combustion.
Definition: The standard enthalpy change of combustion (ΔcH°) is the enthalpy change when 1 mole of a substance is completely burned in oxygen under standard conditions, with all reactants and products in their standard states.
Standard conditions are defined as:
The page also emphasizes that all chemicals must be in their standard states (solid, liquid, or gas) under these conditions.
This section focuses on combustion reactions and how to recognize complete combustion.
Example: The complete combustion of ethane is represented by the equation: C₂H₆(g) + 3.5O₂(g) → 2CO₂(g) + 3H₂O(l)
Key points for combustion reactions:
The page also introduces the method for calculating the standard enthalpy change of combustion using experimental data.
This page provides a step-by-step guide to calculating the standard enthalpy change of combustion using experimental data.
Highlight: The formula q = mcΔT is used to calculate the thermal energy transferred to water during combustion.
Steps for calculation:
This page introduces key equations and concepts for enthalpy change calculations in A Level Chemistry.
Highlight: The equation q = mcΔT is crucial for calculating energy transfer, where q is energy, m is mass, c is specific heat capacity, and ΔT is temperature change.
Vocabulary: Standard enthalpy change (ΔH°) refers to the enthalpy change of any reaction under standard conditions.
The page emphasizes the importance of using standard conditions when determining enthalpy changes and introduces the symbol for standard enthalpy changes.
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Amount of Substance (includes back titration)
Amount of substance equations for chem alevel - includes examples, and long working for a back titration problem
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JJ
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A Level Chemistry Enthalpy Change Calculations: Key Concepts and Formulas
This document covers essential concepts for A Level Chemistry enthalpy change calculations, including standard conditions, enthalpy of combustion, and practical calculations.
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
By signing up you accept Terms of Service and Privacy Policy
This page presents a practical example of calculating the enthalpy change of combustion for ethanol.
Example: Given experimental data:
- Mass of water = 400 g
- Temperature change of water = +36.5 °C
- Mass of fuel combusted = 3.75 g
- Molar mass of ethanol = 46.0 g mol⁻¹
The calculation process is demonstrated step-by-step:
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
By signing up you accept Terms of Service and Privacy Policy
This page focuses on the practical determination of enthalpy change of combustion for liquid fuels.
Highlight: The density of water is 1 g cm⁻³, and its specific heat capacity is 4.18 J g⁻¹ K⁻¹.
Steps for determining enthalpy change of combustion:
Example: Calculation for propan-1-ol combustion:
- 1.50 g of propan-1-ol heated 250 cm³ of water by 45°C
- Heat gained by water: Q = 250 × 4.18 × 45 = 47,025 J
The page emphasizes that combustion reactions are exothermic, releasing heat to the surroundings.
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
By signing up you accept Terms of Service and Privacy Policy
This page delves into the specifics of standard conditions and introduces the concept of standard enthalpy change of combustion.
Definition: The standard enthalpy change of combustion (ΔcH°) is the enthalpy change when 1 mole of a substance is completely burned in oxygen under standard conditions, with all reactants and products in their standard states.
Standard conditions are defined as:
The page also emphasizes that all chemicals must be in their standard states (solid, liquid, or gas) under these conditions.
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
By signing up you accept Terms of Service and Privacy Policy
This section focuses on combustion reactions and how to recognize complete combustion.
Example: The complete combustion of ethane is represented by the equation: C₂H₆(g) + 3.5O₂(g) → 2CO₂(g) + 3H₂O(l)
Key points for combustion reactions:
The page also introduces the method for calculating the standard enthalpy change of combustion using experimental data.
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
By signing up you accept Terms of Service and Privacy Policy
This page provides a step-by-step guide to calculating the standard enthalpy change of combustion using experimental data.
Highlight: The formula q = mcΔT is used to calculate the thermal energy transferred to water during combustion.
Steps for calculation:
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
By signing up you accept Terms of Service and Privacy Policy
This page introduces key equations and concepts for enthalpy change calculations in A Level Chemistry.
Highlight: The equation q = mcΔT is crucial for calculating energy transfer, where q is energy, m is mass, c is specific heat capacity, and ΔT is temperature change.
Vocabulary: Standard enthalpy change (ΔH°) refers to the enthalpy change of any reaction under standard conditions.
The page emphasizes the importance of using standard conditions when determining enthalpy changes and introduces the symbol for standard enthalpy changes.
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
By signing up you accept Terms of Service and Privacy Policy
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
By signing up you accept Terms of Service and Privacy Policy
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
By signing up you accept Terms of Service and Privacy Policy
Free notes for every subject, made by the best students
Get better grades with smart AI support
Study smarter, stress less - anytime, anywhere
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Chemistry - N5 Chemistry - UNIT 1 Summary Sheet
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