EMA4121_HW3_Solutions

# 8 mjm2 why are the values different water has a

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Unformatted text preview: hy are the values different? Water has a dipole moment and thus has an entropy component related to its distribution of orientations. The theoretical calculation doesn’t take the amount of energy required to overcome the entropy contribution into account, so it is higher than the actual value. 2. At 20°C, the surface tensions of water and n-octane are 72.8 mJ/m2 and 21.8 mJ/m2, respectively. And the interfacial tension of the water/octane interface is 50.8 mJ/m2. Calculate: a. The work of cohesion for i. N-octane ( ) ii. Water ( ) b. The work of adhesion between n-octane and water c. The initial spreading coefficient of n-octane on water ( ) 3. A highly viscous silicone oil has a surface tension of about 20 mJ/m2. A small drop of water is placed on a film of the oil. The contact angle measured immediately after the water is placed on the film is 110°. What is th...
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