Question

1. Draw the heating rate curve of water and of ethanol (in one figure) when the same amount in mol) of each are heated up from -20°C to 120°C. Bp. Mp AHp. kJ/mole 40 AHlus kJ/mole Cp(gas). J/(mole.K) H2O C2H5OH °C 0 -115 100 78 Cplice). J/(mole.K) 40 100 Cp(Liq), J/(mole.K) 80 110 40 35 70 2. Explain why the effect of pressure on freezing point of water is different with many other substances? Please make the answer better by using plot of chemical potential vs temperature!

Answer 1

Date ASHA Page Aus Heating rate curve is the curve between temperature and heat supplied. → Let mole of both water and ethanal is equals to 1 mole as given in the question to be equal a Graph are as shown in the lig - ethanol و ساله با - - Hoe - - 18,720 55600 o 800 68001 148001 54800 10,780 45,780 In 1 - region. The state is solid state or ice og region where no state change is taking place. Only temp of the state is increase according to the formula DQ = nCpfice AT

ASHA Date Page - Heren is moles Cocice is heat capacity inice state - DT is temperature difference Q is heat supplied. first region of water a DQ = 1) (40) (@º-6200)) = 800 J For - for 2-region > solid State to cohange occore i.e from / L is enthaly change or AQ=nL for water in 2 regon AQ = (1) (6) = GKJ - 6000 J [ TKJ = 10005] of water > for 3-region or a region - 1 of ethanol Liquid state exist and temp is increased. in liet liquid state. =) Heat capacity in liquid state sa=n Collig) AT | CPCG) AQ - a coleira) (Thind-Timidad)

For water in region 3 AQ=(1) (80) ( 100-0) J - 8000 J for ethanol in region I AQ = (1) (110) (78-1- 20) = 10,780 I - for region 4 of water of region 2 of ethanol state & change occurs ie from liquid to gas Q= n Luap a | trap Enthalpy changin vapour stake or Hvap for water I AQ= (1) (40) = 40 kJ = 40000 ] for ethanol do - 01(35) = 35 KJ = 350005

→ region 5 of water of region 3 of ethanal temperature increase af & in vapour state takes place. DQ = nCP egas, AT ( Copes, Heat capacity in 2 gaseous state / for water AQ - (1) (40) (120-100) = 800J for ethanol AQ² (1) (70) (120-78) = 2,9405