Question

Identify which property of water cohesion, adhesion, or heat capacity applies to each observation below.

Answer 1

4. Large, circular lily pads are able to float on the water's surface.

Answer: cohesion

Cohesion mean that water attracted to another water. This force will make the water to form a surface tension in the lake. Water lily has a wide and thin leaf which makes it giving a low force per area. If the force applied on the surface is not bigger than surface tension, the leaf will stay float above the water. Surface tension also the reason water spider could walk on water.

5. The temperature of the water is about 5°C, while the temperature of the air is about 21°C.

Answer: heat capacity

Water has high heat capacity. High heat capacity mean that the water will not be easily become cold or hot. It will need more energy to increase/decrease the temperature of the water. This is why the water could keep its temperature much lower than the atmosphere. This will protect the organism inside the water from an extreme temperature change.

Answer 2

Answer:

For 4: The correct answer is adhesion

For 5: The correct answer is heat capacity.

Explanation:

Adhesive forces are defined as the molecular forces which are present between different substances. For Example: When water is poured into glass, the molecular forces between the walls of container and water molecules.

Cohesive forces are defined as the molecular forces which are present between same substances.

Heat capacity is defined as the amount of heat energy that is required to raise temperature of a substance per unit of mass. It is a physical property.

• For 4:

The molecular forces between circular lily pads and water is strong. Thus, circular lily pads float on water's surface.

Hence, the correct answer is adhesion.

• For 5:

In water, hydrogen bonding is present, which is strong. So, in order to overcome this bonding, we need to apply more heat. So, the amount of heat required is more to raise the temperature. Thus, it has high heat capacity.

This is the reason the temperature of water is about 5°C while the temperature of air is about 21°C.

Hence, the correct answer is heat capacity.