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