Ch.6 - Thermochemistry WorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Sections
Internal Energy
Calorimetry
Hess's Law
Enthalpy of Formation
End of Chapter 6 Problems
Additional Practice
Units of Energy
Endothermic & Exothermic Reactions
Additional Guides
Enthalpy

Solution: Zinc metal reacts with hydrochloric acid according to the following balanced equation. Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g) When 0.116 g of Zn(s) is combined with enough HCl to make 52.3 mL of solution in a coffee-cup calorimeter, all of the zinc reacts, raising the temperature of the solution from 21.5 °C to 24.7 °C. Part AFind ΔHrxn for this reaction as written. (Use 1.0 g/mL for the density of the solution and 4.18 J/g • °C as the specific heat capacity.)

Problem

Zinc metal reacts with hydrochloric acid according to the following balanced equation. 

Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g) 

When 0.116 g of Zn(s) is combined with enough HCl to make 52.3 mL of solution in a coffee-cup calorimeter, all of the zinc reacts, raising the temperature of the solution from 21.5 °C to 24.7 °C. 

Part A

Find ΔHrxn for this reaction as written. (Use 1.0 g/mL for the density of the solution and 4.18 J/g • °C as the specific heat capacity.)