Essentials of Water

Water is essential for life. Its special properties make water the single most important molecule in plant life. Which of the following properties of water enables it to move from the roots to the leaves of plants?

• Water expands as it freezes.

• Water is an excellent solvent.

• Water exhibits cohesive behavior.

• Water is able to moderate temperature.

Tags

NGSS.MS-ESS2-4

Large bodies of water, such as lakes and oceans, do not quickly fluctuate in temperature. What is the reason for this phenomenon?

• Water is an acid.

• Water is a versatile solvent.

• Water has a high heat capacity.

• Water acts as a buffer.

Tags

NGSS.MS-PS3-4

Why does ice stay at the top of oceans instead of sinking to the bottom?

• Ice is colder than liquid water.

• Ice is less dense than liquid water.

• Ice is more dense than liquid water.

• Ice is warmer than liquid water.

Water is often called the "universal solvent" because many substances can be dissolved in water. What property of water allows it to be such a versatile solvent?

• purity

• polarity and cohesion

• high heat capacity

• expansion upon freezing

Water has a much higher specific heat than most other covalent compounds. What do you predict might happen if water had a low specific heat instead?

• Flooding would occur and animals would be forced to migrate

• Harmful organisms living in water would reproduce at a rapid rate

• Organisms that are sensitive to changes in temperature would die

• Plants would not have enough water to effectively carry out photosynthesis

Tags

NGSS.MS-LS2-4

Small insects can walk across the surface of calm water. Their feet push the surface of the water down slightly, somewhat like a person walking across a trampoline, but they do not break the surface. What is the best explanation for why this happens?

• The insects are light enough so that they do not break the hydrogen bonds holding the water molecules together

• The insects actually use their wings to hover slightly above the water's surface and they only skim it with their feet

• The insects' feet are non-polar, so they are repelled by the polar water molecules and are pushed away from the water's surface

• The insects are small enough to see the individual water molecules, so they are able to step carefully from one molecule to the next

A florist places a bouquet of white carnations in water containing blue dye. After a time, the flowers turn blue. What process helped the carnations to change color?

• Specific heat

• Surface tension

• Cohesion and adhesion of water molecules

• Formation of covalent bonds between hydrogen and oxygen molecule

Tags

NGSS.MS-PS1-2

Maria, after finding no cold sodas in the refrigerator, placed a can of soda in the freezer. She then proceeded to check her social networking site and forgot about the soda. Later that evening her brother went to get some ice and it was brown. Maria’s soda can had split open. What is the best explanation for what happened?

• As the water cooled, it adhered to the can, causing it to split

• When the water froze, the space between hydrogen molecules expanded

• When the water froze, it weakened the molecular bonds in the aluminum can

• As the water cooled, the surface tension of the water decreased and the can collapsed

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Water is essential for life. Its special properties make water the single most important molecule in plant life. Which of the following properties of water enable it to move from the roots to the leaves of plants?

• Water expands as it freezes

• Water is an excellent solvent

• Water exhibits cohesive behavior.

• Water is able to moderate temperature.

Tags

NGSS.MS-ESS2-4

Many fish and aquatic plants can survive a cold winter because the layer of ice that forms at the top of the lake insulates the water below and prevents the lake from freezing solid. What unique property of water contributes to this effect?

• Water absorbs heat when it evaporates and forms a gas

• Water expands and becomes less dense when it freezes.

• Water molecules completely separate into ions in solutions.

• Water forms hydrogen bonds with ions and other polar substances.

Tags

NGSS.HS-ESS2-5