interfacial phenomena

Question 1

Surface tension define and equation

Answer 1

the unequal distribution of forces between molecules at the interface compared to the bulk phase .

Question 2

why does water have a higher surface tension than most liquids

Answer 2

water molecule are small molecules but have high surface tension this is because of the strong interactive forces b/w water molecules (h-bonds)

Question 3

how is forces of attraction b/w molecules affected by temperature

Answer 3

as temperature increases energy input into the system increases decreasing the force of attraction between molecules

Question 4

what is the impact of solutes on surface tensions

Answer 4

increase solutes increases surface tensions as there are more interactive forces

Question 5

what is the wilhelmy plate

Answer 5

used to measure surface and interfacial tension. the force which the liquid uses to hold the plate down is measured and used to calculate surface tension.

Question 6

define cohesion and adhesion

Answer 6

cohesion :force of attraction between molecules of same substance
adhesion: force of attraction between molecules of different substances

Question 7

what is contact angle (angle made with interface)

Answer 7

if its hydrophilic than contact angle is less than 40 if angle is greater than 90 than hydrophobic