Estimate the surface tension of pure methanol at 20ºC, density 791.7 kg/m^3, molecular weight 32.04.

Question

Estimate the surface tension of pure methanol at [latex]20^{\circ} C ext {, density } 791.7 kg / m ^{3}[/latex], molecular weight 32.04.

Accepted Answer

Calculation of parachor, [latex]CH _{3} OH[/latex], Table 8.7.

Table 8.7. Contribution to Sugdens’s parachor for organic compounds (Sugden, 1924)
Atom, group or bond	Contribution	Atom, group or bond	Contribution
C	4.8	Si	25.0
H	17.1	AI	38.6
H in (OH)	11.3	Sn	57.9
O	20.0	As	50.1
[latex]O _{2} ext { in esters, acids }[/latex]	60.0	Double bond: terminal
N	12.5	2,3-position	23.2
S	48.2	3,4-position
P	37.7	Triple bond	46.6
F	25.7	Rings
CI	54.3	3-membered	16.7
Br	68.0	4-membered	11.6
I	91.0	5-membered	8.5
Se	62.5	6-membered	6.1

[latex]\sigma=\left[\frac{87.4 imes 791.7}{32.04} ight]^{4} imes 10^{-12}=\underline{\underline{21.8} mJ / m ^{2}}[/latex] (8.23)

[latex] ext { Experimental value } 22.5 mJ / m ^{2} ext {. }[/latex]

Question 8.13: Estimate the surface tension of pure methanol at 20ºC, densi...