Chapter 11.1

Question 1

What percent of the world is freshwater?

Answer 1

3%

Question 2

What is salinity?

Answer 2

Salinity is a measure of the quantity of dissolved salt in water. It is expressed as a percentage or g/L.

Question 3

What is concentration?

Answer 3

Concentration is a measure of the quantity of a dissolved substance contained per unit volume of a solution.

Question 4

When an object is more dense than the liquid, will it sink or float?

Answer 4

Sink

Question 5

What is desalination?

Answer 5

Desalination is the technology of removing salt and other minerals from water. It produces pure water and solid salt.

Question 6

Why is desalination expensive?

Answer 6

Desalination is expensive because the process requires lots of thermal energy to evaporate the water.

Question 7

What are two renewable energy sources that can be used in the deslination process?

Answer 7

Solar energy and geothermal energy

Question 8

What are the two common processes of desalination?

Answer 8

1. Heating salt water so the water evaporates, leaving the salt behind. The evaporated water vapour is then condensed back into a liquid, using a cooling process.
2. Using osmosis across a membrane with tube-like pores called nanotubes. The tiny pores prevent salt and other particles from passing through.