Question

4. In an experiment, when 23.6 of calcium chloride, CaCl2 were dissolved in water in a coffee- cup calorimeter (at constant pressure), the temperature rose from 25.0°C to 38.7°C. The dissolution process is: CaCiz(s) - Ca2+ (aq) + 2C1-(aq) The heat capacity of the solution and the calorimeter is 1258 J/°C. The molar mass of CaCl2 is 110.98 g/mol. 1) Determine the heat that was absorbed by the solution and calorimeter. (1 point) 2) Determine the heat that was released from the dissolution of CaCl, in the experiment. (1 point) 3) Calculate the enthalpy change, AH, of the dissolution written as the given equation. (i.e. Find the heat released for 1 mole of CaCl, dissolving in water therefore AH = 1 (1 point) 4) How much heat would evolve when 1.20 mole of CaCl2 dissolves in water? (1 point) The first line of the Lyman series of the hydrogen atom emission results from a transition from the n = 2 level to the n = 1 level. What is the wavelength of the emitted photon? Describe the region of the electromagnetic spectrum in which this emission lies. (2 points)

Answer 1

4P Heat absonbed by the solution a calonimetēr heat capacity x change i temper ature 1258 J/c x (38.7- 250) °C 17234. 6 J 2) Heat nelensed brom the dissolution d Cacy heat absonbed b the solution auw calonimetēr 7234.6 J 23.6 0.213 mol 3) Moles d Ca taken 110.48 gmol 17234.6 J S0.9 k/mol 80913.6 T/mol O.213 mol 4) J mol Cau, pnoduces So.9 kJ heat Cay go,a x1.2 kJ hent heat 97.0g kJ aye-

Ryebeng Equation 5. whene, R Rydbeng comtant 109737 em wavelengt d emited phaton (cm) ane prinaipel quantam number d lotoer a higher euergy levels nespectively. 1 22 - 109737 12 =1.215 X1 .215 X10 em The aNe is : This emissian lies i the wttraviolet (Uv) negio d the electromaguet medrum. page-2