Interpretation:
The
Concept Introduction:
Enthalpy of reaction:
The enthalpy of a reaction is calculated by subtracting the heat of formation of reactants from heat of formation of products.
Exothermic and Endothermic Reaction:
Exothermic reaction is a reaction in which heat is given out to the surrounding from the system.
Endothermic reaction is a reaction in which heat is gained by the system from the surrounding.
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Chapter 21 Solutions
General Chemistry - Standalone book (MindTap Course List)
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- In the commercial preparation of aluminum, aluminum oxide, Al2O3, is electrolyzed at 1000C. (The mineral cryolite is added as a solvent.) Assume that the cathode reaction is Al3+3eAl How many coulombs of electricity are required to give 3.9 kg of aluminum?arrow_forwardAluminum is produced commercially by the electrolysis of Al2O3 in the presence of a molten salt. If a plant has a continuous capacity of 1.00 million A, what mass of aluminum can be produced in 2.00 h?arrow_forwardElectrolysis of a solution of CuSO4(aq) to give copper metal is carried out using a current of 0.66 A. How long should electrolysis continue to produce 0.50 g of copper?arrow_forward
- Comparing the chemistry of carbon and silicon. (a) Write balanced chemical equations for the reactions of H2O() with CH4 (forming CO2 and H2) and SiH4 (forming SiO2 and H2). (b) Using thermodynamic data, calculate the standard free energy change for the reactions in (a). Is either reaction product-favored at equilibrium? (c) Look up the electronegativities of carbon, silicon, and hydrogen. What conclusion can you draw concerning the polarity of CH and SiH bonds? (d) Carbon and silicon compounds with the formulas (CH3)2CO (acetone) and [(CH3)2SiO]n (a silicone polymer) also have quite different structures. Draw Lewis structures for these species. This difference, along with the difference between structures of CO2 and SiO2, suggests a general observation about silicon compounds. Based on that observation, do you expect that a silicon compound with a structure similar to ethene (C2H4) exists?arrow_forwardHydrazine, N2H4, has been proposed as the fuel in a fuel cell in which oxygen is the oxidizing agent. The reactions are N2H4(aq) + 4 OH(aq) N2(g) + 4 H2O() + 4e O2(g) + 2 H2O() + 4e 4 OH(aq) (a) Which reaction occurs at the anode and which at thecathode? (b) What is the overall cell reaction? (c) If the cell is to produce 0.50 A of current for 50.0 h, calculate what mass in grams of hydrazine must be present. (d) Calculate what mass (g) of O2 must be available to reactwith the mass of N2H4 determined in part (c).arrow_forwardData are given in Appendix 1 for white phosphorus, P4(s). P4(g) has the following thermodynamic values: Hf=58.9kJ/mol , S=280.0J/kmol . What is the temperature at which white phosphorus sublimes at 1 atm pressure?arrow_forward
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