Modifying Biology Chapter 3 Quiz
A mole of methanol (CH3OH) weighs 32 g. The number of grams of methane that are needed to produce 1 L of a millimolar solution is __________.
0.032 g
Urine, at pH 6, contains __________ H+ as household bleach, at pH 13.
10,000,000 times as much
A solution at pH 10 contains __________ than the same amount of solution at pH 8.
100 times less H+
You can fill a glass of water to just slightly above the rim without it spilling over the glass. What property of water best explains this phenomenon?
Surface tension
__________ is an emergent property of water that allows insects like the raft spider to walk on water.
Surface tension
Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?
The absorption of heat by the breaking of hydrogen bonds.
A substance that reduces the hydrogen ion concentration of a solution is ___________.
a base
An acid is __________.
a compound that donates hydrogen ions to a solution
Water molecules have __________ than molecules of similar size, such as ammonia and methane, reflecting its capacity to absorb large amounts of heat.
a higher boiling point
The absorption of human-generated CO2 by the oceans __________.
all of the listed responses are correct -increases the oceans' acidity and lowers pH -increases the oceanic concentration of carbonic acid -increases the hydrogen ion concentration in the oceans but decreases the carbonate ion concentration and threatens the livability of the oceans for calcifying organisms -reduces the carbonate ion concentration in the oceans and threatens calcifying organisms in marine ecosystems
A compound that donates hydrogen ions to a solutions is __________.
an acid
Hydrophilic molecules __________.
are charged molecules that are attached to the partial charge of the water molecule
Hydrophobic molecules __________.
are uncharged, nonionic substances that seem to repel water
The ability of water molecules to form hydrogen bonds with other water molecules an water's ability to dissolve substances that have charges or partial charges are __________.
bother caused by water's partial charges
The phenomenon responsible for maintaining the upward movement of water through a vessel is __________.
cohesion
Water moves up a plant because of hydrogen bonds by a process called
cohesion and adhesion
Sweating has a cooling effect because of water's high __________.
heat of vaporization
When ice forms, the __________ are farther apart than in liquid water, allowing the ice to form an organized crystal structure and float.
hydrogen bonds
Nonpolar molecules that cluster away from water molecules are called __________ molecules.
hydrophilic
When the pH of a solution shifts from 3 to 7, the hydrogen ion concentration has changes, and __________.
it has decreased by 10,000 times
Glucose has a molecular mass of 180 daltons. To make a 2-molar (2 M) solution of glucose, __________.
stir 360 g of glucose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 1 L
Buffers are __________.
substances that minimize changes in the concentration of H+ and OH- in a solution
The specific heat of a 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
Adhesion is best described as __________.
the clinging of one substance to another substance
The amount of heat required to convert 1 g of any substance from the gaseous state is defined as __________.
the heat vaporization of that substance
Water is a polar molecule. This means that __________.
the opposite ends of the molecule have opposite electrical charges
The amount of heat required to change the temperatures of 1 g of any substance by one *C is defined as __________.
the specific heat of that substance
The partial charges on a water molecule occur because of __________.
the unequal sharing of electrons between the hydrogen and the oxygen atoms of a water molecule
When the pH of a solution shifts from 3 to 7, the hydrogen ion concentration has changed, and __________.
it has decreased by 10,000 times When the pH of a solution shifts from 3 to 7, hydrogen ion concentration has changed, and it has decreased by 10,000 times. The pH scale compresses the range of H= and OH- concentrations b employing logarithms. The pH of a solution is defined as the negative logarithm (base 10) of the hydrogen ion concentration; pH log [H+]. For a neutral aqueous solution, [H+] is 10^-7 M, giving is log 10^-7=-(-7). Notice that pH declines as H+ concentration increases. Remember that each pH unit represents a tenfold difference in H+ and OH- concentrations. It is this mathematical feature that makes the pH scale so compact. A solution of pH 3 is not twice as acidic as a solution of pH 6, but a thousand times (10x10x10) more acidic. Because the pH number is the negative log of the hydrogen ion concentration, a change from a pH to 7 to a pH of 3 increases the hydrogen ion concentration by 10,000 times (7-3=4; [10x10x10x10] 10^4=10,000).
Adding a base tends to __________ of a solution.
lower the hydrogen ion concentration and increase the pH
All of the following are hydrogen bonding properties except __________.
nonpolar covalent bonding Surface tension, adhesion, partial changes on the oxygen and hydrogen, a cohesion are hydrogen bonding properties, but nonpolar covalent bonding is not. Water's polar nature is responsible for these properties. The extraordinary qualities of water are emergent properties resulting from hydrogen bonding. The properties in question refer to the electrical attraction between something and a water molecule or between water molecules.