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The following problems are to be submitted next week, but you should work on the

ID: 555118 • Letter: T

Question

The following problems are to be submitted next week, but you should work on them today with your group. #3425pts) The propulsion system for the space shuttle orbiter uses the reaction 5 N2040) 4 N2H3CH(l)12 H20(g) + 9 N2(g) +4 CO2(g) (kJ/mole) for this reaction using data in Appendix III of your Calculate the AH textbook as well as H (kJ/mole) of N2H3CHs(I) = 54.0 kJ/mol and H"(kJ/mole) of N2041)20.0 kJ/mol #4425pts) A lecture demonstration is being planned to illustrate an endothermic reaction. It is desired to lower the temperature of 1100.0 g of water in an insulated dissolved in the water to achieve this result? The heat of solution of NH4CI (s) is NH4Cl(s) > NH4+(aq) + Cl.(aq) AHsolno_ +14.8 kJ/mole container from 21.5 to 5.00 degrees C. Approximately what mass of NH Cl (s) should b Data: Swater 4.184 J/(g °C)

Explanation / Answer

HRXn = Hproducts - HReactants

HRxn = 12H2O + 9N2 + 4CO2 - (5N2O$ + 4N2H3CH3)

HRxn = 12*-241.8 + 9*2 +4*393.5 - (5*-20 + 4*54)

HRxn = -1425.6 kJ

Q4.

mass of NH4Cl required for

Q = m*C*(Tf-Ti)

Q = 1100*4.184*(5-21.5)= -75939.6 J

75939.6 J must be abosbred

Qrxn = n*HRX

75939.6 = n*14.8*1000

n = (75939.6) /(14.8*1000) =

n = 5.13105 mol of NH4CL

mass = mol*MW = 5.13105*53.49146 = 274.46g of NH4Cl will do