Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 36m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

8. Thermochemistry

Thermochemical Equations

General Chemistry

8. Thermochemistry

Thermochemical Equations

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Multiple Choice

A 100.0 mL sample of 0.300 M NaOH is mixed with a 100.0 mL sample of 0.300 M HCl in a coffee cup calorimeter. If both solutions were initially at 35.00°C and the temperature of the resulting solution was recorded as 37.00°C, determine the ΔH°rxn (in kJ/mol) for the neutralization reaction.

-10.0 kJ/mol

-55.8 kJ/mol

-75.0 kJ/mol

-25.0 kJ/mol

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Verified step by step guidance

Identify the reaction: The neutralization reaction between NaOH and HCl is NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l).

Calculate the total volume of the solution: Since both solutions are mixed, the total volume is 100.0 mL + 100.0 mL = 200.0 mL.

Determine the number of moles of NaOH and HCl: Use the molarity formula, M = moles/volume (L). For NaOH, moles = 0.300 M × 0.100 L = 0.0300 moles. Similarly, for HCl, moles = 0.300 M × 0.100 L = 0.0300 moles.

Calculate the heat absorbed by the solution using q = mcΔT: Assume the density of the solution is similar to water (1.00 g/mL) and specific heat capacity is 4.18 J/g°C. The mass of the solution is 200.0 g. ΔT = 37.00°C - 35.00°C = 2.00°C. Thus, q = 200.0 g × 4.18 J/g°C × 2.00°C.

Convert the heat absorbed to kJ and calculate ΔH°rxn: Since the reaction involves 0.0300 moles of NaOH and HCl, divide the heat absorbed by the number of moles to find ΔH°rxn in kJ/mol. Remember to convert the heat from J to kJ by dividing by 1000.