Water and Life

What is the only common substance to exist in the natural environment in all three physical states of matter

Water

What are the chemical bonds in water

Polar covalent

What is more electronegative oxygen or hydrogen

Oxygen

In a water molecule what partial electric charge does oxygen have

Negative

In a water molecule what partial electric charge does hydrogen have

Positive

What are the four emergent properties of water contribute to Earth's suitability for life

Cohesive behavior

Ability to moderate temperature

Expansion upon freezing

Versatility as a solvent

Cohesion of water molecules is brought about by what

Hydrogen bonding

Surface tension of water is caused by what

Hydrogen bonding between water molecules

What is kinetic energy

Energy of motion

What is thermal energy

Kinetic energy associated with atoms or molecules

What is temperature

The measure of the average kinetic energy of the molecules in a body of matter

What is heat

Thermal energy is transfer from one body of matter to another

What is a calorie

The amount of heat required to raise the temperature of 1 g of water by 1°C

What is specific heat

The amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1°C

Why does water resist changes in temperature

because it has a high specific heat

Why is the specific heat of water high

Because hydrogen bonds have first to be broken which absorbs the thermal energy

Heat of vaporization

It is the heat a liquid must absorb for 1 g to be converted to gas

What happens to the density of water as it freezes

gets less dense

What is a solution

It is a liquid that is a completely homogeneous mixture of substances

What a solvent

It is the dissolving agent of a solution

What is a solute

It is the substance that is dissolved

What is an aqueous solution

It is one in which water is the solvent

When an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules called what

a hydration shell

What is a hydrophilic substance

It is one that has an affinity for water

What is a hydrophobic substance

It is one that does not have an affinity for water and can actually repel it

What type of substances are hydrophobic

Nonionic and nonpolar they cannot form hydrogen bonds with water and cannot dissolve

How do you calculate molar mass

Add the atomic masses of every atom in the molecule

What is an acid

Any substance that increases the H+ concentration of a solution.

What is a base

Any substance that reduces the H+ concentration of a solution

What is a strong acid

One that completely dissociates in solution

What is a weak acid

One that only partially dissociates in solution

What is pH

The negative logarithm of H+ concentration

what is the pH of a neutral solution

7

What is the pH of an acidic solution

Anything below 7

What is the pH of an basic solution

Anything above 7

What is the pH of a solution with a hydrogen ion concentration of 10−4 M

4

What is the pH of a solution with a hydrogen ion concentration of 10−10 M

10

What is a buffer

A chemical that minimizes changes in concentrations of H+ and OH− in a solution

What type of chemicals make good buffers

Weak acids

Is the H+ concentration in a pH 5 solution 3 times greater than in a pH 8 solution.

No it is a 1000 times greater as the pH scale is a log scale