Water is called the universal solvent because:

• it can dissolve many substances.

• it is a liquid at room temperature.

• it is colorless and odorless.

• it has a high boiling point.

Define salinity.

• Salinity is the total concentration of dissolved salts in seawater.

• Salinity is the measure of water temperature.

• Salinity is the amount of sunlight in a given area.

• Salinity is the concentration of oxygen in the air.

Match the following salinity levels with their descriptions.

• Salinity of freshwater.

• 35 parts per thousand (ppt) or 35‰.

• Average salinity of ocean water.

• 40 parts per thousand (ppt) or 40‰.

• Salinity of the Dead Sea.

• 30 parts per thousand (ppt) or 30‰.

• Salinity of brackish water.

• 25 parts per thousand (ppt) or 25‰.

What is chemical equilibrium in the context of ocean water?

• A state where the chemical composition of ocean water remains constant over time.

• A point where ocean water becomes acidic.

• A condition where ocean water evaporates completely.

• A situation where ocean water freezes.

List the sources of ions in the ocean.

• River runoff, Volcanic eruptions, Hydrothermal vents, Atmospheric deposition (dust and gases).

• Photosynthesis, Respiration, Decomposition, Evaporation.

• Sedimentation, Erosion, Precipitation, Condensation.

• Tidal forces, Ocean currents, Wind patterns, Solar radiation.

Match the factors with their contribution to ocean layer formation.

• Factors affecting water stratification.

• Temperature, Salinity, Density.

• Factors influencing ocean currents.

• Sunlight, Moonlight, Starlight.

• Factors affecting ocean illumination.

• Wind patterns, Moon phases, Tides.

• Factors related to ocean biodiversity.

• Marine life, Coral reefs, Algae.

The pH of the ocean is (a)  

• 7.5
• 8.1
• 9.0
• 6.5

Mark an X on the graph where the water from the deepest part of the ocean is located, indicating higher density and lower temperature.

• At the top left corner of the graph

• At the top right corner of the graph

• At the bottom left corner of the graph

• At the bottom right corner of the graph

The salinity is low at the Equator because (a)  

• there is high evaporation.
• there is high precipitation.
• there is low temperature.
• there is high salinity.

Salinity is high at the Tropics because:

• there is more evaporation than precipitation.

• there is more precipitation than evaporation.

• there are more rivers flowing into the sea.

• there is less sunlight.