Q: Which of the following equations best describes the relationship for capillary rise ($$h) in a $$tube of radius $$r$$?

$$h = \frac{2\gamma \cos \theta}{\rho g r}$$

Question 1

Which of the following best describes the difference between cohesive and adhesive forces?

Accepted Answer

Cohesive forces are the attraction between molecules of the same substance, while adhesive forces are the attraction between molecules of different substances.

Question 2

A drop of water is placed on a piece of wax paper. The drop forms a nearly spherical shape. Which force is primarily responsible for this shape?

Accepted Answer

Cohesive forces between water molecules

Question 3

Which of the following liquids would you expect to have the highest surface tension at room temperature?

Accepted Answer

Water

Question 4

Capillary action is observed when water rises in a thin glass tube. Which combination of forces is responsible for this phenomenon?

Accepted Answer

Both cohesive and adhesive forces

Question 5

Which equation correctly represents the relationship between surface tension ($$\gamma$$), force ($$F$$), and length ($$L) $$for a liquid film?

Accepted Answer

$$\gamma = F / L$$

Question 6

A student observes that water climbs higher in a capillary tube than mineral oil. What is the best explanation for this observation?

Accepted Answer

Water has stronger adhesive forces to glass than mineral oil.

Question 7

Which of the following best explains why polar liquids generally have higher surface tension than nonpolar liquids?

Accepted Answer

Polar liquids have stronger intermolecular forces, such as hydrogen bonding.

Question 8

If the diameter of a capillary tube is doubled, what happens to the height ($$h) $$the liquid rises, assuming all other factors remain constant?

Accepted Answer

$$h is $$halved

Question 9

Which of the following is a real-life application of capillary action?

Accepted Answer

Movement of water from roots to leaves in plants

Question 10

A drop of glycerin spreads out more on glass than a drop of water. What does this indicate about the adhesive and cohesive forces of glycerin compared to water?

Accepted Answer

Glycerin has stronger adhesive forces to glass than water.

Question 11

Which of the following best describes the effect of intermolecular forces on the shape of a liquid drop?

Accepted Answer

Stronger intermolecular forces make the drop more spherical.

Question 12

Which of the following substances would you expect to have the lowest capillary rise in a glass tube?

Accepted Answer

Hexane

Question 13

A student uses a tensiometer to measure the force required to break the surface of a liquid. Which property is being measured?

Accepted Answer

Surface tension

Question 14

Which of the following best explains why water beads up on a freshly waxed car surface?

Accepted Answer

Cohesive forces in water are stronger than adhesive forces between water and wax.

Question 15

Which of the following equations best describes the relationship for capillary rise ($$h) in a $$tube of radius $$r$$?

Accepted Answer

$$h = \frac{2\gamma \cos 	heta}{ho g r}$$

Question 16

Which of the following statements about hydrogen bonding is correct?

Accepted Answer

Hydrogen bonding is a strong intermolecular force found in polar molecules like water.

Question 17

A student finds that the tilt angle required to move a drop of water on glass is greater than that for hexane. What does this indicate?

Accepted Answer

Water has greater adhesive forces to glass than hexane.

Question 18

Which of the following best explains why nonpolar substances tend to have lower surface tension?

Accepted Answer

Nonpolar substances have weaker intermolecular forces.

Question 19

Which of the following is NOT a consequence of surface tension?

Accepted Answer

Water boiling at a lower temperature

Question 20

Which of the following best describes the relationship between surface tension and drop diameter for a given volume?

Accepted Answer

Higher surface tension results in a smaller drop diameter.

Cohesion, Adhesion, Surface Tension, and Capillary Action: Study Notes

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