Properties of Water Quiz

Polarity

Polar Covalent bonds created by unequal sharing of electrons between oxygen and hydrogen within the molecules of water.

Cohesion

Attraction of molecules for other molecules of the same kind (H2O to H2O)

• Hydrogen bonds between H20 molecules hold them together and increase cohesive forces.

• Allows for the transport and nutrients against gravity in plants.

• Responsible for surface tension.

  • Surface H2O molecules experience greater pull because there are no molecules above them to balance the forces.

Adhesion

The attraction to other molecules that are polar or have charge (H2O to other molecules)

• Due to polarity of H2O.

  • In plants, this allows water to cling to the cell walls to resist the downward pull of gravity.

Capillary Action

The upward movement of water due to the forces of cohesion, adhesion, and surface tension.

• Occurs when adhesion is greater than cohesion.

• Important for transport of water and nutrients in plants.

Temperature Control

High specific heat: H2O resist changes in temperature.

• How? Hydrogen Bonds! Heat must be absorbed to break hydrogen bonds, but heat is released when hydrogen bonds form.

• Importance: Moderates air temperature, stabilizes ocean temperature, organisms can resist changes in their own internal temperature,

High heat vaporization: Water requires a large amount of energy to evaporate due to strong hydrogen bonds.

• Importance: Moderate’s earth climate, stabilizes temp in lakes and ponds, prevents terrestrial organism from overheating, prevents leaves from becoming to warm in sun.

Density

As water solidifies it expands and become less dense.

• Due to hydrogen bonds.

• When cooled, H2O molecules move too slowly to break the bonds.

  • Allows marine life to survive under floating ice sheets.

Solvent

Dissolving agent in a solution.

• Water is a versatile solvent.

  • It’s polar molecules are attracted to ions and other polar molecules it can form hydrogen bonds with.

  • Solution: homogenous mix of 2+ substances, Solvent: dissolving agent, Solute: substance dissolves.

pH and buffering

pH: measure how acidic or basic a solution is

Buffer: a solution that resists change in pH when an acid or base is added.

Water as a medium for metabolic processes in cells

Water is a universal solvent as it can dissolve more substances than water.

• Ability to break a part other bonds and work its way into open spaces around other molecules.

• Circulatory and urinary system: Water dissolves metabolic waste which allows them to be filtered from the blood and excreted in urine.

Water’s ability to moderate temperature in organisms and the environment

Because water has high specific heat it can resist changes in temperature through hydrogen bonds! In doing so, it moderates air temperature (large bodies of water can absorb heat in the daytime and release heat at night), stabilizes ocean temperature, and organisms can resist changes int her own internal temperature.

The movement of water from roots to leaves in plants

Cohesion keeps molecules connected together through the attraction of molecules for other molecules of the same kinds, and adhesion helps water stick to the xylem wall through the attraction to other molecules. The properties work together to help to help water move upward from the roots to the leaves. where it is used in photosynthesis and eventually loss through transpiration.

Why water is considered a good solvent for many substances

Water is a good, versatile solvent because its polar molecules are attracted to ions and other polar molecules it can form hydrogen bonds with.

How hydrogen bonding affects the behavior of water

Hydrogen bonding has a major effect on the behavior of water because water molecules are polar, in which the hydrogen side is slightly positive and the oxygen is slightly negative. As a result, these bonds contribute to cohesion, adhesion, high specific heat, surface tension, and ice being less dense than liquid water.

The importance of cohesion between water molecules

Cohesion is the attraction of molecules for other molecules of the same kind allowing them to transport water and nutrients against gravity in plants. It is also responsible for surface tension!

The importance of adhesion between water and other surfaces

Adhesion is the attraction to other molecules that are polar or have charge allowing water to stick to surfaces like the xylem wall and move upward contributing to capillary action.

How water’s high specific heat helps maintain stable temperatures

Water’s high specific heat allows it to absorb large amounts of heat with only small temperature changes largely because of their hydrogen bonds . This moderates air temperature because large bodies of water can absorb heat int he daytime and release heat at night and stabilized ocean temperature.

How evaporative cooling helps organisms regulate temperature

As water molecules evaporate, the surface they evaporate from gets cooler. This helps to moderate earth’s climate, stabilize temps in lakes and ponds, and prevent overheating.

Why ice floats and how this benefits aquatic ecosystems

Is floats due to density! As water solidifies it expand and becomes less dense due to its hydrogen bonds.This insulates the water below, allowing aquatic ecosystems to remain habitable during cold temperatures.

How water’s polarity contributes to its biological importance

Water’s polarity gives it many of its important biological properties. Since it has partial positive and negative charges it can form hydrogen bonds, dissolve polar molecules, participate in chemical reactions, and interact with other polar substances.

How surface tension results from the properties of water

Water molecules experience cohesion from the attraction of molecules from other molecules of the same kind. This is responsible for surface tension in which the surface water molecules experience greater inward pull because there are no molecules above them to balance the forces.