PAC 110 BASIC CHEMISTRY

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Course Content
Naming of Simple Compounds and Chemical Thermodynamics (09 May 2023).pptx
CHEMICAL THERMODYNAMICS (15 MAY 2023).pptx
PAC 110 Atomic Structure and Chemical Bonding (3 April 2023).pptx
Chemical Bonding and Atomic Structure (27 March 2023).pptx
Atomic Structure (06 March 2023).pptx
Atomic Structure - 27 February 2023.pptx
PAC 110 BASIC CHEMISTRY INTRO 2023.pptx
PAC 110 course content to be taught by (Prof B.A. Aderibigbe)
PAC 110 course content to be taught by (Prof B.A. Aderibigbe)

Lecture 1: Basic concepts of matter
Lecture 1: Basic concepts of matter

Self-practice exercises (1) on Basic concept of matter.pdf
Basic concepts of matter (2) Discussion
Matter can change from one state to another. Discuss factors that contribute to matter to changing states.
Matter can change from one state to another. Discuss factors that contribute to matter to changing states.

Lecture notes on Chemistry and measurement
Lecture notes on Chemistry and measurement

Chemistry and Measurement 1.pdf
Lecture 3 notes (Chemistry and Measurement wih Prof Aderibigbe).pdf
Acid, Bases and Redox Equilbria
Gases part 2 (Prof B. Aderibigbe)
Thermochemistry lectures
Thermochemistry lectures

PAC 110 MAKE UP TEST (PROF B. ADERIBIGBE) 27TH MAY 2023
Due date: 5/27/23, 9:00 AM
Time limit: 120 minutes
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PAC 110 MAKE UP TEST (PROF B. ADERIBIGBE) 27TH MAY 2023
PAC 110 MAKE UP TEST (PROF B. ADERIBIGBE) 27TH MAY 2023
19 minutes remaining
7 OF 38 QUESTIONS REMAINING
Test Content
Page 32 of 38

Question 32
3
Points
The table below shows some values for standard enthalpy changes of combustion.

Substance

incrementHc Ө / kJ mol−1

C(s)

−394

H2(g)

−286

CH4(g)

−890

Use these values in the table above to calculate the standard enthalpy change of the reaction

C(s) + 2H2(g) ® CH4(g)

-210 kJ

-604 kJ

-76 kJ

-318 kJ

Answer 1

The correct answer is -76 kJ.

To calculate the standard enthalpy change of the reaction, we need to use Hess's Law, which states that the total enthalpy change of a reaction is independent of the path taken to get from the reactants to the products.

First, we need to write the balanced chemical equation for the reaction:

C(s) + 2H2(g) → CH4(g)

Next, we can use the enthalpy changes of combustion for each substance to calculate the enthalpy change for the reaction:

ΔHrxn = ΣΔHc°(products) - ΣΔHc°(reactants)

ΔHrxn = [ΔHc°(CH4)] - [ΔHc°(C) + 2ΔHc°(H2)]

ΔHrxn = [-890 kJ/mol] - [-394 kJ/mol - 2(-286 kJ/mol)]

ΔHrxn = -76 kJ/mol

Therefore, the standard enthalpy change of the reaction C(s) + 2H2(g) → CH4(g) is -76 kJ/mol.