Given the following data at 1 atm of pressure and 25.0 °C...ΔH°formation = +64.4 kJ/mole for Cu²⁺.ΔH°formation = -152.4 kJ/mole for Zn²⁺.ΔH°formation = 0 for both Zn and Cu²⁺ because these are in the most stable state.Calculate the standard heat of reaction for........Zn(s) + Cu2+ (aq) →Zn2+(aq) + Cu(s)
Correct answer: A. -217 kJ/mole
- A. -217 kJ/mole
- B. +217 kJ/mole
- C. -88.0 kJ/mole
- D. +88.0 kJ/mole
Explanation
To calculate the standard heat of reaction, use the formula ΔH°reaction = ΣΔH°f,products - ΣΔH°f,reactants. The enthalpies of formation are given as follows: ΔH°f(Zn²⁺) = -152.4 kJ/mole and ΔH°f(Cu²⁺) = +64.4 kJ/mole. The elements in their standard states, Zn(s) and Cu(s), have enthalpies of formation of 0 kJ/mole. Therefore, ΔH°reaction = [-152.4 kJ/mole] - [64.4 kJ/mole] = -216.8 kJ/mole, which rounds to -217 kJ/mole. Options B, C, and D do not account correctly for the given enthalpy values.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Thermochemistry and Energetics of Chemical Reactions
Thermochemistry measures energy changes in chemical reactions and distinguishes exothermic from endothermic processes. Work covers systems, surroundings and state functions, internal energy, the first law of thermodynamics, enthalpy and Hess's law, including the sign conventions used when heat enters or leaves a system.
Practise Thermochemistry and Energetics of Chemical Reactions
729 free Thermochemistry and Energetics of Chemical Reactions MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Chemistry questions like this
Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Thermochemistry and Energetics of Chemical Reactions questions
The heat of combustion for 1 mole of carbon to carbon dioxide is -410 kJ. How many kJ of heat would be liberated from the complete combustion of 60.0 g of carbon?
Water has a specific heat of 4.184 J/g deg while glass (Pyrex) has a specific heat of 0.780 J/g degree. If 10.0 J of heat is added to 1.00 g of each of these, which will experience the larger increase in temperature?
If 1 J of heat is added to a 2.00 g sample of aluminum metal, and the temperature of the metal increases by 1°C, what is the specific heat of aluminum?
Which statement describes characteristics of an endothermic reaction?
Given the following information, calculate the heat of formation of C₂H4Cl₂(g) in kJ/mole:2 C(s) + 2 H₂(g) + Cl₂(g) → C₂H4Cl₂(g)2 C(s) + 2 H₂(g) → C₂H4(g) ΔH°/kJ = +52.3kJC₂H4Cl₂(g) → Cl₂(g) + C₂H4(g)ΔH°/kJ = +116kJ
Calculate the value of ΔH°/kJ for the following reaction using the listed thermochemical equations:N₂(g) + 1/2O₂(g)→N2O(g)2NH₃(g) + 3N2O(g)→4N₂(g) + 3H₂O(l), ΔH°/kJ = -1010kJ4NH₃(g) + 3O2(g)→2N₂(g) + 6H₂O(l), ΔH°/kJ = -1531kJ