Bio Chapter 3 Quiz

How does water make life possible on Earth

It is the only common substance to exist in the environment3 in all three states of matter, its unique emergent properties help make earth suitable for life, and the structure of the water molecules allow it to interact with other molecules.

What type of molecule is water and why

Water is a polar molecule as the electrons of the polar covalent bonds in water spend more time near the oxygen than the hydrogen. The overall charge is unevenly distributed. Polarity allows water moecules to form hydrogen bonds.

How can you determine the amount of hydrogen bonds that can be formed?

Look for N, O, and F. Then look for H directly bonded to N, O, or F. Water has 4

What are the four properties of water that contribute to earth?

Cohesive behavior, ability to moderate temperature, Expansion upon freezing, versatility as a solvent.

Cohesion and Adhesion of water

Hydrogen bonds hold water molecules together, a phenomenon known as cohesion, which helps the transport of water against gravity in plants. Adhesion is an attraction between different substances (water and plant cells)

What is surface tension and how does it relate to water?

Surface tension is a measure of how difficult it is to break the surface of a liquid, and water has a high surface tension due to hydrogen bonding between molecules at the air-water interface, and water below

How does Water moderate temperature?

Water absorbs heat from warmer air, and releases stored heat to cooler air. Water can absorb or release a large amount of hear with only a slight change to its temp.

Kinetic Energy vs Temperature

Kinetic energy is the energy of motion, and the kinetic energy associated with random motion of atoms or molecules: thermal energy

Temperature is the average kinetic energy of molecules in matter, and the transfer of thermal energy from one body to another is heat

What is specific heat and how does it relate to water

Specific heat is the amount of heat energy needed to raise one g of a substance by 1 C, 1cal/gC

Water resists changing temp due to its high specific heat

Why does water have a High Specific heat?

Water has a high specific heat due to hydrogen bonding, and heat is absorbed when hydrogen bonds break, and is released when hydrogen bonds form.

What is Heat of Vaporization and evaporative cooling?

Heat of Vaporization is the heat of a liquid must absorb for 1g to be converted to a gas, however, as a liquid evaporates its remaining surface cools known as evaporative cooling. Evaporative cooling of water helps stabilize temps in organisms and bodies of water.

Why does Ice float on water?

Ice floats in liquid water as hydrogen bond sin ice are more ordered, making ice less dense than water, water reaches greatest density at 4C, and if ice sank, all bodies of water would freeze solid, making life impossible on Earth. (hydrogen bonds stable)

What is a Solution, solvent, solute, and a type of solution.

A solution is a liquid that is a completly homogeneous (same) mixture of substance

Solvent: substance that does the dissolving

Solute: substance that is dissolved

Aqueous solution: water is the solvent.

Is water versatile,, and what is a hydration shell?

Water is a versatile solute due to its polarity, and when an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules, known as a hydration shell.

What else can water dissolve?

Water can also dissolve compounds made of nonionic polar molecules, and even large polar molecules such as proteins can dissolve in water if they have ionic and polar regions.

Hydrophobic vs hydrophillic substance

Hydrophilic: loves water (polar)

Hydrophobic: Hates water (non-polar)

Oil molecules are hydrophobic= due to nonpolar bonds

Hydrophobic molecules related to oils are major ingredients of cell membranes.

Describe what can happen to a hydrogen atom

A hydrogen atom in a hydrogen bond between two molecules can shift from one to another

If the atom leaves its electron behind and is transferred as a proton, or hydrogen ion (H+)

Molecule that lost the proton is now a hydroxide ion (OH-)

Molecule with the extra proton is a hydronium ion (H30+)

What is an Acid and A base

An acid is a substance that increases H+ concentration

A base reduces H+ concentration

Strong acids and bases dissociate completely in water, weak acids and bases reversibly release and accept back hydrogen ions, but can shift balance of H+ and OH- away from neutrality

Name all 3 PH Values

Acidic Solutions have PH values less than 7

Basic have pH values greater than 7

Most biological fluids have pH values in the 6 to 8 range

Things to remember

Ph 1 = 10x more hydrogen than two, increases as you go down by 10