PS5_2011

# PS5_2011 - Name: Section: Rec TA: Side 1 of 3 Ch 1b,...

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Name: Ch 1b, Problem Set Five Section: Side 1 of 3 Due Friday, Feb. 11, 2011 Rec TA: at 4 PM in the Drop Box 1. Enthalpy Change & Phase Transitions (24 points) Calculate Δ H (units: kJ) for this process: Process Start: 2.00 mol of steam at 130 ° C Process End: 2.00 mol of ice at –15.0 ° C Use Δ Ĥ fusion = 6.01 kJ mol -1 and Δ Ĥ vap = 40.7 kJ mol -1 for the specific molar heats of fusion and vaporization, respectively, at their transition temperatures. (NOTE: Sometimes you’ll see a carat over the symbol for enthalpy when it has units of energy per unit mole and it’s called specific molar enthalpy. Other times people will just use the same symbol, H (without the carat), for enthalpy, specific molar enthalpy and specific mass enthalpy – watch the units closely to determine if you have to multiply by the number of moles or the mass.) You may assume that specific molar heat capacity (see Table below) is independent of temperature for each phase. Heat capacity ( c P ) J mol -1 K -1 Ice 38.0 Liquid water 74.5 Steam 36.0 You may treat steam as an ideal gas, and you may assume the process is isobaric. 2. Adiabatic Flame Temperature (21 points) Acetylene, C 2 H 2 (g), is commonly used in welding. When acetylene is burned in oxygen, the reaction is: (a) Use data from Appendix D in OGC to calculate

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## This note was uploaded on 03/21/2011 for the course CHEMISTRY 1b taught by Professor Reisman;heath during the Winter '11 term at Caltech.

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PS5_2011 - Name: Section: Rec TA: Side 1 of 3 Ch 1b,...

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