Question

1. Heating causes the internal energy of 1.0 kg of some substance to change from a solid at -174°C to a gas at +158°C, as shown in the graph below. Determine the following: (a) The freezing-melting temperature. 114 (b) The boiling-condensing temperature. 70 (e) The specific heat capacity of the solid. I *2KJ= (1.069) 631-11.4°C-1-174°()) TIC G2 1.2 KJ/g °C As demp mrezas, energy increcies (d) The specific heat capacity of the liquid. = 6 , 637-176 kJ 461 MOT T (1.0) (78-114) 192 =2.4k] . Q=AQ T=DT +72= (10kg)ch I up -4°C-(-174°C)) (e) The specific heat capacity of the gas. (1) The latent heat of fusion. (8) The latent heat of vaporization. (h) Now write a mathematical expression that includes the total heating needed to convert the 1.0 kg of matter from - 174°C to +158°C. Q061 = Qs+QF+Ql+ Qv+Qg

i tried working on it but I am a little lost. Sorry for the messy work covering the page.

Answer 1

Solution

a)

To determine the melting-freezing temperature, we rely on the graph shown:

we know that the melting point is the temperature at which matter changes from a solid to a liquid state, while the freezing point is the reverse process. Then the temperature at the melting-freezing temperature, the matter changes phase, but the temperature is the same

Therefore, the process starts in solid from -174 ° C to -114 ° C and then changes to a liquid phase, from -114 ° C to 78 ° C and finally to gas from 78 ° C to 158 ° C

Then, in reference to the graph shown, the melting-freezing temperature is -114°C

b)In reference to the heat vs. temperature graph, the boiling-condesination point is 78 ° C, where the liquid boils at the same temperature

c) To obtain the heat capacity of the solid, we use the following expression

(1)

77CSI =ܠ

Then

$C_{e}=\frac{\Delta Q}{m\Delta T}$ (2)

72kJ 1kg * [-114°C - (-174°C) = 0.25kJ/kg°C

d) Now, for the heat capacity of the liquid

637kJ – 176kJ 7 = 2.40kJ/kg°C 1kg * 178°C - (-114°C)

e) For, the heat capacity of the gas

Ce = 1kg* 1555kJ – 1491kJ 1kg * (158°C - (78°C) v = 0.8kJ/kg°C

f)

The latent heat of fusion is defined as the heat that requires a mass of 1 kg to change its solid to liquid state. In equation form it is expressed

ܠ Q = 77 : L

72kJ - = 2kJ/kg 1kg m

g)

Now, the latent heat of vaporization

L-42_6376:17.2762:7 – 4616.7/kg m 1kg