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Physical Chem

Graph 1 shows the cooling curves of mixtures of naphthalene and diphenylamine, with higher diphenylamine concentrations lowering the freezing point more. Graph 2 shows the opposite effect for mixtures of diphenylamine with naphthalene. The phase diagram in Graph 3 shows the naphthalene-diphenylamine system has a eutectic point at around 57% diphenylamine. Graph 4 determines the heat of fusion of naphthalene is 25.04 kJ/mol from the graph of log X vs 1/T.

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1K views4 pages

Physical Chem

Graph 1 shows the cooling curves of mixtures of naphthalene and diphenylamine, with higher diphenylamine concentrations lowering the freezing point more. Graph 2 shows the opposite effect for mixtures of diphenylamine with naphthalene. The phase diagram in Graph 3 shows the naphthalene-diphenylamine system has a eutectic point at around 57% diphenylamine. Graph 4 determines the heat of fusion of naphthalene is 25.04 kJ/mol from the graph of log X vs 1/T.

Uploaded by

hazwani safura
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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A) Naphthalene + Diphenylamine

Cooling curve graph


100

90

80

70

60
Temperature, °C

50

40

30

20

Time, s
10

0
0 30 60 90 120 150 180 210 240 270 300

Pure Naphthalene N + 0.5g DPA N + 1.0g DPA N + 1.5g DPA N + 2.0g DPA

Graph 1
N-Naphthalene
DPA-Diphenylamine
B) Diphenylamine + Naphthalene

Cooling curve graph


60

50

40
Temperature , °C

30

20

Time, s
10

0
0 30 60 90 120 150 180 210 240 270 300

Pure DPA DPA + 0.5g N DPA + 1.0g N DPA + 1.5g N DPA + 2.0g N

Graph 2
DPA- Diphenylamine
N- Naphthalene
Phase diagram of naphthalene-diphenylamine system
Diphenylamine Naphthalene
90

80 D

Liquid
70

60

Solid
Naphthalene
Freezing point, °C

50 + Liquid

C Solid Diphenylamine + Liquid


40 E

30

Solid
20 Diphenylami
ne + Solid
Naphthalene
10

0
0 0.25 0.4 0.5 0.57 0.64 0.73 0.84 1
Composition

Phase Diagram Naphthalene-Diphenylamine


Graph log X vs 1/T for naphthalene
0
0.0125 0.0147 0.0156 0.0182 0.0233
0

-0.05 -0.0757

-0.1
-0.137
Log X

-0.15
-0.194
-0.2
-0.244
-0.25

-0.3
1/T (°C-1)

Graph 3
−0.22−(−0.05)
m=
0.00255−0.00242

= -1307.69

−∆𝐻° 1
log 𝑋 = ( )
2.303 𝑅 𝑇

−∆𝐻°
= 𝑔𝑟𝑎𝑑𝑖𝑒𝑛𝑡
2.303 𝑅

−∆𝐻°
= −1307.69
2.303 𝑥 8.314

∆H° = 25.04 kJ/mol


Thus, heat of fusion for naphthalene is 25.04 kJ/mol

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