chapter 3 : water and life

properties of water that emerge as a result of its ability to form hydrogen bonds

Cohesion and adhesion are the results of hydrogen bonds

In a washing machine, the detergent raised the pH to 9.0. The concentration of OH- in the solution is ...

In a washing machine, the detergent raised the pH to 9.0. The concentration of OH- in the solution is ...

Which of the following is not true of water?

Its evaporation helps regulate body temperature

Why isn't this insect drowning? (Pic is of a bug sitting on the surface of water) It is difficult to change the temperature of water.

Surface tension.

hydroxide ion (OH−)

The molecule that lost the proton

hydronium ion (H3O+)

The molecule with the extra proton

Which property of water contributes to the upward movement of water in a tree?

cohension

polarity of water molecules causes

them to be attracted to each other

hydrogen bonds

- weak , but takes alot of energy to overcome the combined attraction of many hydrogen bonds, each water molecule can hydrogen bond to four other water molecules

A stalk of celery is placed in a container of blue dye. After one hour the leaves have blue fluid in their veins. Which of the properties of water are being demonstrated?

-Cohesion and adhesion

Factory smoke has led to acid rain that lowered the pH of a lake to 5.0. What is the H+ concentration in the lake?

10- 5 M , The pH is the negative exponent of the H+ concentration.

Whats the hydrogen ion (H+) concentration of pH 8

10^-8

The most hydrophobic molecule is

Cholesterol

heat is released when hydrogen bonds

FORM

Which types of molecules are attracted to water?

Hydrophilic

If one were to add a strong acid like HCl to an aqueous solution, which would result?

More hydronium ions would form in the solution

Which statement best explains the physical basis for why oil (molecules containing only carbon and hydrogen) and water do not mix?

Oils are nonpolar molecules that cannot interact with water molecules via hydrogen bonding.

What conditions must be met in order for an aqueous solution to be called "neutral"?

The concentrations of hydronium and hydroxide ions are equal.

Which of the following is true when comparing solutions with a pH of 6 and a pH of 8?

The solution with a pH of 8 has a 100 times lower concentration of hydrogen ions than a solution with a pH of 6.

The hydrogen bonds among water molecules endow water with which property?

Water has a high specific heat.

Which of the functional groups is polar and acts like a base?

carboxyl group

The strongest possible chemical link between two atoms is a(n)

covalent bond (juju and V)

solvent

dissolving agent of a solution

Concentrations of H+ and OH− are

equal in pure water

What are trans fats?

fats that contain trans double bonds and may contribute to atherosclerosis

As one form of energy is converted into another, there is always some energy lost as

heat

COhension (co hoe they grind and transport cum (water) against bodies)

helps the transport of water against gravity in plants -hydrogen bonds hold water molecules together, a phenomenon called cohesion ex: trees move water up by losing water ya feel me ...

What type of bonding is likely to occur between two water molecules or strands of DNA?

hydrogen

Surface tension of water is due to

hydrogen bonding

when ice floats in water

hydrogen bonds in ice are more ORDERED allowing ice to become less dense then water -Water reaches its greatest density at 4°C

Why does the sand get so hot at the beach but the water feel so cool?

hydrogen bonds takes a lot of energy to overcome the combined attraction of many hydrogen bonds. This explains water's great capacity to store heat, its high boiling point, surface tension, and several other unusual properties.

hydrogen atom leaves its electron behind and is transferred as a proton

hydrogen ion (H+)

Rank the following chemical bonds from weakest to strongest:

hydrogen, ionic, covalent

The plasma membrane is made up of a phospholipid bilayer, with the _____________ of the phospholipids_____________.

hydrophilic heads // sticking out toward the interior and exterior of the cell

hydration shell

ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules

aqueous solution

is one in which water is the solvent

evaporative cooling

liquid evaporates, its remaining surface cools -helps stabilize temperatures in organisms and bodies of water

solution

liquid that is a completely homogeneous mixture of substances

hydrophilic

loves water ; affinity for water

Surface tension

measure of how hard it is to break the surface of a liquid Water has an unusually high surface tension due to hydrogen bonding between the molecules at the air-water interface and to the water below ex: spider walking on f***ing WATER MAGIC

water is a polar molecule... is the charge even ?

no because one side of the molecule is being slightly positive and the other end of the molecule being slightly negative

Molarity (M)

number of moles of solute per liter of solution

base:

pH above 7 more OH- (hydroxide ions); reduces the H+ concentration of a solution

acid :

pH below 7 is acidic more [H+] ( hydrogen ion); that increases the H+ concentration of a solution

pH:

pH of a solution is defined by the negative logarithm of H+ concentration 7 - neutral

Which kinds of bonds are present in a single water molecule?

polar covalent bonds

is water a polar or nonpolar molecule

polar molecule

polar covalent bonds allow

polarity allows water molecules to form hydrogen bonds with other water molecules

In the water molecule, electrons of the polar covalent bond

spend more time near the oxygen than the hydrogen

specific heat

substance is the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1°C -specific heat of water is 1 cal/g/°C

solute

substance that is dissolved

Explain how buffers work

substances that minimize changes in concentrations of H+ and OH- in a solution and consist of acid- base pair ; help keep a constant pH

Molecular mass

sum of all masses of all atoms in a molecule

Heat of vaporization

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

True or False. Hydrogen bonds occur between two or more water molecules.

true

We maintain a fairly constant body temperature despite exposures to different seasons or external temperatures. This is achieved through our capacity to

adapt to changing environments, regulate body temp, and maintain homeostasis (all)

hydrophobic

afraid of water ex : oil they are nonpolar bonds

adhension

attraction between different substances, for example, between water and plant cell walls water sticking sticky cummm

heat is absorbed/taken in when hydrogen bonds

break