College Biology: Chapter 2 Smartbook - The Chemical Basis of Life

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if 3 grams of sodium chloride are dissolved in enough water to make 12 liters, what is the concentration of the solution?

0.25 g/L

the molecular mass of glucose is 180g. if 90g of glucose are dissolved in enough water to make 1L, what is the molarity of the solution?

0.5 M

a solution at pH 6 is more acidic than a solution at pH 7 because the concentration of H⁺ (protons) is ___ times higher than that in a solution pH 7

10

each change of one pH unit represents a ___ difference in H⁺ concentration

10-fold

in pure water, the concentrations of H+ and OH- ions are:

10^-7 M each

if a solution has a pH of 8, what is the concentration of protons in the solution?

10^-8 M

the atomic mass of carbon is 12, and the atomic mass of hydrogen is 1. what is the molecular mass of a methane molecule (CH4)?

16

the atomic mass of hydrogen is 1, and the atomic mass of oxygen is 16. what is the molecular mass of a water molecule (H2O)

18

if 1 gram of glucose is dissolved in a total volume of 0.5 L, what is the concentration of the solution?

2 grams per liter

what is the normal pH range of living cells?

6.5-7.8

in humans, water compromises approximately ____ of body weight

60-70%

when water ionizes, it produces what ions?

H+ and OH-

what contributes to waters stability in a liquid state?

a high heat of vaporization, a high heat of fusion

a substance that relates hydrogen ions into a solution is called an?

acid

if you add H+ ions to a solution, it becomes more:

acidic

a solution at pH 5 is said to be ______ because it contains more ______

acidic; H+ ions than OH- ions

with respect to pH, blood in the human body is within a narrow range of values that are considered to be slightly:

akaline

arrange the following solutions in order of increasing proton concentration. the solution with the lowest proton concentration should be placed at the top: neutral akalkine acidic

akaline neutral acidic

Aasolution in which water is the solvent is called a _____ solution.

aqueous

in pure water, what are the concentrations of H⁺ and OH⁻ ions each?

are the concentrations of H⁺ and OH⁻ ions each [H⁺] = 10⁻⁷ M, [OH⁻] = 10⁻⁷ M

a substance that absorbs hydrogen ions in a solution is called a?

base

in animals, what buffer is primarily responsible for maintaining the pH of body fluids?

bicarbonate

a polar covalent bond is created when?

bonded atoms have unequal pull on the shared electron, so that the electron spends more time around one atom than the other

hydrolysis reactions:

break apart molecules via water

what type of compound minimizes pH fluctuations in the fluids of living organisms?

buffers

what mechanisms help organisms to regulate their internal pH?

buffers, elimination of H+ into the urine (via the kidneys)

heat ____ refers to the amount of heat energy required to raise the temperature of an entire object, such as a body of water

capacity

which of the following molecules are predicted to easily dissolve in water?

carbohydrates that contain OH- groups, ions that carry full electric charges

living organisms are mainly composed of which atoms?

carbon, hydrogen, nitrogen, and oxygen

which of the following changes in the physical state of water require the input of energy?

changing from solid to liquid, changing from liquid to gas

the phenomenon of water molecules attracting one another is known as ______ whereas the process of water molecules being attracted to non-neutral surfaces is known as ________

cohesion, adheison

properties of a solution that depend strictly on the total number of dissolved solutes, and not the specific type of solute, are called _____ properties

colligative

properties of a solution that depend strictly on the total number of dissolved solutes, and not the specific type of solute, are called ________ properties

colligative

the amount of solute (in grams) dissolved in a given volume of solution is the solution's:

concetration

the addition of solutes to water will?

decrease its freezing point, increase its boiling point

ice floats in liquid water because ice has a lower ______ than liquid water

density

because exercise produces lactic acid, it may:

descrease the pH of body fluids

select all of the following that describe molecules that only have hydrophobic regions

dissolve well in non polar solvents, contain many non polar covalent bonds, relatively insoluble in water

what describes molecules that only have hydrophobic regions?

dissolve well in non-polar solvents, relatively insoluble in water, contain many non-polar covalent bonds

the ability of an atom to attract electrons in a bond with another atom is termed its?

electronegativity

when water vaporizes at an ordinary temperature, the process is known as?

evaporation

compared with liquid water, ice has?

greater hydrogen bonds between individual water molecules, a more orderly arrangement of water molecules

an amphipathic molecule:

has polar and non-polar regions

compared to a small puddle of water, a lake has?

higher heat capacity, but the same specific heat

hydrochloric acid is considered an acid because it releases _______ ions into solution

hydrogen

the considerable amount of heat it takes to boil water is due to the collective strength of many _____ bonds

hydrogen

water clings to surfaces to which it can form a _______ bond

hydrogen

when water is heated, the rate at which _______ bonds break increases, and water molecules are converted to the ______ state

hydrogen, gaseous

amphipathic molecules have both ______ regions and ______ regions

hydrophillic, hydrophobic

a base will release ____ ions when dissolved in water

hydroxide

which molecules are predicted to easily dissolve in water?

ions that carry electric charges, carbohydrates that contain OH- groups

what property of water makes it a good solvent?

it's ability to form hydrogen bonds

which state of water is the most dense?

liquid

which component of humans has the greatest percent of water?

lungs

when mixed with water, amphipathic molecules may aggregate into spheres called

micelles

when mixed with water, amphipathic molecules may aggregate into spheres called?

micelles

the sum of the atomic masses of all atoms in a molecule is equal to the molecule's _________ mass

molecular

pH is defined as the ____ ____ to the base of 10 of the ___ concentration

negative logarithm, H+

hydrophobic molecules tend to contain many ________ covalent bonds, such as the bond between two carbon atoms or the bond between carbon and hydrogen

non-polar

what type of bonds are most likely to be found in a hydrophobic molecule?

non-polar covalent

colligative properties depend on the _____ dissolved in a solution

number of particles

the ____ of a solution is the negative base 10 logarithm of the H⁺ concentration of the solution

pH

the unequal sharing of electrons between the oxygen and hydrogen atoms within a water molecule makes water a ____ molecule

polar

pure water can ionize into?

positively charged protons (H⁺) and negatively charged hydroxide (OH⁻) ions

acid rain can ____ the pH of water entering the roots of plants

reduce

to freeze water, energy is?

released

what has the lowest freezing temperature? sea water water in an office water cooler lake water sugar water, as in soda

sea water

the kidneys can help organisms cope with changes in pH by?

secreting acidic compounds into the bloodstream, secreting alkaline compounds into the bloodstream, transferring hydrogen ions from the fluids of the body into the urine

the concentration of a liquid is defined as the amount of ________ dissolved in a unit volume of solution

solute

substances dissolved in liquid are known as?

solutes

substances dissolved in liquids are known as?

solutes

solutes dissolved in a solvent form a?

solution

hydrochloric acid is called a ____ acid because it almost completely dissociates into H⁺ and Cl⁻ when added to water

strong

____ is a measure of the attraction between molecules of water at the surface of a liquid due to hydrogen bonding

surface tension

polar covalent O-H bonds in water molecules enable hydrogen bonds to form between water molecules. what properties of water result from hydrogen bond formation?

surface tension, high heat of vaporization, adhesion, high specific heat, cohesion,

what is the heat of fusion of a substance?

the amount of heat energy released when 1 mole of the substance is converted from liquid to solid

place the physical states of water in order based on the intermolecular distances between water molecules. the top position should be the state in which the molecules are the farthest apart: the solid state the liquid state the gaseous state

the gaseous state, the liquid state, the solid state

define heat of vaporization

the heat energy required to convert 1 mole of a substance from liquid to gas

define specific heat

the heat energy required to raise the temperature of 1 gram of a substance by 1 degree celsius

define heat of capacity

the heat energy required to raise the temperature of an entire object

define heat of fusion

the heat energy that must be withdrawn or released from a substance to convert it from liquid to solid

water has a high heat of vaporization because of?

the high number of hydrogen bonds between molecules

what part of an amphipathic molecule would be oriented toward the center of a micelle?

the non-polar region

what is the molarity of a solution?

the number of moles of a solute in 1 liter

what happens to the pH of a solution whenH⁺ ions are added to it

the pH decreases

in a micelle, which portion of the amphipathic molecules are oriented toward the surface of the sphere?

the polar region

when water freezes?

the rate of hydrogen bond breakage slows, water molecules are packed into a less dense formation, the H2O molecules in ice are in a much more orderly arrangement than in the liquid state

the molecular mass of a molecule is equal to

the sum of the atomic masses of all atoms in one molecule

describe hydrophillic molecules

they are soluble in water

what describes hydrophilic molecules?

they're soluble in water

even though it requires energy to change water from a liquid to a gas, some water molecules break their hydrogen bonds at an ordinary temperature (evaporate) by:

vibrating at a higher energy

rank each of the types of water from increasing density, starting with the lease dense state at the top: ice, liquid water, water vapor

water vapor, ice, liquid water

carbonic acid is called a ______ acid because some of it remains in the H2CO3 state when dissolved in water

weak


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