Unit 3 - Hydrosphere and Atmosphere

Water is a unique molecule due to its polar nature, which arises from the arrangement of its atoms. A water molecule consists of two hydrogen atoms bonded to one oxygen atom. The oxygen atom attracts electrons more strongly than the hydrogen atoms, leading to an uneven distribution of charge within the molecule. This results in the oxygen atom having a slight negative charge (δ-) and the hydrogen atoms having a slight positive charge (δ+). This polarity allows water molecules to form hydrogen bonds with each other and with other polar molecules or ions. Why is water considered a polar molecule, and what are the consequences of its polarity? (3.1)

• Water is a polar molecule because the hydrogen atoms attract electrons more strongly than the oxygen atom, resulting in hydrogen bonds that repel other molecules.
• Water is a polar molecule because the oxygen atom attracts electrons more strongly than the hydrogen atoms, leading to an uneven distribution of charge within the molecule, allowing it to form hydrogen bonds with other polar molecules or ions.
• Water is a polar molecule because it has an even distribution of charge throughout the molecule, making it non-reactive with other substances.
• Water is a polar molecule because the hydrogen and oxygen atoms share electrons equally, leading to no charge difference within the molecule, allowing it to form hydrogen bonds with non-polar molecules.

Students are performing an experiment to test the properties of water. They place five white flowers into five cups that contain dyed water. They leave the flowers in the cups for a few days and record the results. The image shows the experiment setup. Which property of water are the students most likely trying to show by performing the experiment? (3.1)

• capillary action, because it shows how colored dye will float above the water
• surface tension, because it shows how colored dye will float above the water
• capillary action, because it shows the movement of dyed water against gravity
• surface tension, because it shows the movement of dyed water against gravity

Which property of water is directly attributable to its molecular structure and polarity? (3.1)

• High specific heat capacity
• Strong cohesion
• Low viscosity
• Low density

Use the following information to answer the question:

• The bonds between water molecules are weaker in fresh water than in salt water.
• The bonds between water molecules are stronger in fresh water than in salt water.
• The water molecules in fresh water are larger than the water molecules in salt water.
• The water molecules in fresh water are smaller than the water molecules in salt water.

Look at the diagram to answer the question that follows. If a northern coastline such as the Norway coast is located near a warm ocean current then...? (3.2)

• the climate will be colder than normal for that latitude.
• the climate will be warmer than normal for that latitude.
• spring is longer than normal for that latitude.
• spring is shorter than normal for that latitude.

Because water can hold a large amount of heat, which effect do oceans have on nearby land areas? (3.2)

• They prevent rapid extreme temperature changes.
• They form high-pressure areas that cause magma currents.
• They provide the energy that triggers volcanic events.
• They lower the freezing point of fresh water.

________ and _______ affect the ocean's density and cause the Global Conveyor Belt to travel. (3.2)

• gravity and the Coriolis Effect
• temperature and salinity
• wind and climate

Ocean currents affect global climates. The Great Ocean Conveyor Belt is shown. Which is MOST likely the mechanism that drives the current to continue to circulate? (3.2)

• surface winds
• Differences in density
• rotation of Earth
• gravity of the Moon

The Gulf Steam current travels from the equator toward Europe. If the Gulf Stream stopped flowing, which environmental change would MOST likely occur? (3.2)

• More reefs would develop in the waters near the eastern Greenland coastline.
• Water temperatures in the Northern Atlantic Ocean would be much hotter.
• Land masses in the Northern Atlantic Ocean would have colder climates.
• Most of Europe would be flooded because of rising sea levels.

Which factor is most responsible for distributing heat throughout Earth’s oceans?

• the Coriolis effect
• Earth’s rotation on its axis
• surface and deepwater currents
• boundaries between the oceans and landmasses