pH and Hydrosphere

Hydrosphere

Let's review your learning in Module 9.0 - Investigating Hydrosphere

Multiple Choice

Because of the high surface tension of water, which of the following occurs?

• Some animals resist temperature changes and give off heat.

• The bottom of lakes does not freeze in winter.

• Raft spiders can walk across the surface of a pond.

SURFACE TENSION

•The tightness across the surface of water that is caused by the polar molecules pulling on one another.

•Makes the surface act like a solid

Multiple Choice

A property of water that is responsible for the transport mechanism of water from the roots to the xylem and leaves of plants.

• high specific heat

• cohesion

• adhesion

• capillarity

CAPILLARY ACTION

•The combined force of attraction among water molecules and with the molecules of the surrounding material.

•Cohesion + Adhesion

Multiple Choice

If water samples (click the table/photo) were tested for its drinking quality, which sample/s failed to pass the Philippine National Standards for Drinking Water of 2017?

• X and Z

• Y and Z

• W and Z

Philippine National Standards for Drinking Water of 2017

The maximum allowable limit of TDS is 600 ppm and the pH range should be from 6.5 to 8.5.

Source: https://www.fda.gov.ph/wp-content/uploads/2020/10/Administrative-Order-No.-2017-0010.pdf

Multiple Choice

Which water sample (click the table/photo) probably has the highest salinity level?

• Z

• Y

• X

Salinity and Conductivity

Salts dissolve in water to produce an anion and a cation. These ions make up the basis of conductivity in water. Conductivity is a measure of water’s capability to pass electrical flow. Therefore, salinity of the water sample is directly proportional to its EC (conductivity).

Multiple Choice

Which water sample (click the table/photo) has a neutral pH level?

• W

• X

• Y

• Z

pH of 7 is considered as neutral

Multiple Choice

Which of the following statements BEST describes step G (click the photo)?

• Heat transfer occurs because of a sudden temperature difference as water goes on the earth’s surface.

• It occurs when excess rainwater flows on the earth’s surface, back to the bodies of water.

Multiple Choice

What is/are the main cause/s of the phenomenon in step F (click the photo)?

• saturated air and dew point

• heat transfer from gas to liquid

• very high temperature

Multiple Choice

What occurs when water molecules lose heat and form hydrogen bonds, resulting in a three-dimensional crystal lattice?

• freezing

• evaporation

• precipitation

• condensation

Multiple Choice

What properties of water BEST explain the phenomenon in the figure?

• surface tension and density

• high specific heat and vaporization

• adhesion and cohesion

Cohesion & Adhesion

Cohesion

Water molecules like to stick to each other.

Adhesion

Water molecules like to stick to other things.

Multiple Choice

Which among the following statements is NOT true about water temperature?

• It may differ from time to time

• It affects the amount of dissolved oxygen in water.

• It affects the rate of photosynthesis of water plants.

Multiple Choice

Which of the given points EXACTLY differentiates the rate of heating/cooling of water and land?

• Water heats up and cools down faster than land.

• Land heats up and cools down faster than water.

• Water heats up slower but cools down faster.

Special Pointers in Hydrosphere

Study on different water conservation strategies that can potentially help address the threat of water shortage in the Philippines. Refer to the photo as your guide.

END OF REVIEW LESSON