Biology LS2

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what does it mean when we say water is adhesive?

it is attracted to other polar molecules and ions

what is the temperature of a substance a measure of?

how fast its molecules are moving

electrons that are farther from the nucleus always have which of the following?

more potential energy

which of the following bonds involves the sharing of one or more pairs of electrons?

covalent bond

solid water is *blank* dense than liquid water

less

chemical bonds that form due to the attraction between oppositely charged atoms that have gained or lost electrons are what bonds?

ionic bonds

of the following list of bonds and interactions, which one is the weakest?

hydrophobic interaction

atoms are composed of a central nucleus which is surrounded by which orbiting particles?

electrons

what particles' number and cofiguration determines the chemical behavior of an atom?

electrons

in living organisms, almost all chemical reactions are catalyzed by protein catalysts called what?

enzymes

in living systems, which of the following catalyze almost every chemical reaction necessary for life?

enzymes

an element has five electrons in its outer shell. As such, it needs how many electrons to fill its outer energy level

3

the attraction of water to other polar substances

adhesion

ionic bonds involve which of the following?

an attraction between atoms with opposite electrical charges; a transfer of electrons from one atom to another

hydrogen bond

attraction between a covalently bound H atom with a slight positive charge and another covalently bound atom with a slight negative charge

ionic bond

attraction between oppositely charged atoms

what is a substance or a mixture of substances that act to resist changes in pH?

buffer

the number and configuration of electrons determines an element's what?

chemical properties

what bond is water consisting of one oxygen atom joined to two hydrogen atoms by two single polar bonds

covalent

rank the following bonds and interactions in order from strongest to weakest starting with the strongest at the top. When ranking the bonds, assume that they occur in a biological system, i.e. chemical compounds are dissolved in water.

covalent bond; ionic bond; hydrogen bond; hydrophobic interaction; van der waals attraction

a hydrogen bond can form between the partially negative *blank* atom of one water molecule and the partially positive *blank* atom of another water molecule

oxygen; hydrogen

substances or a mixture of substances known as buffers, act in living things to resist changes in what?

pH

if two atoms are joined by a polar covalent bond, what partial charge does the atom with the lower electronegativity have?

positive

the atoms in NaCl are held together by what type of bond?

ionic

a hydrogen ion, formed during the dissociation of water, has a charge of which of the following?

+1

when 1g of fructose is dissolved in 500mL of water, *blank* is the solvent and *blank* is the solute

water; fructose

van der waals attraction

weak attraction between atoms due to oppositely polarized electron clouds

anything that has mass and occupies space is defined as what?

matter

a group of atoms held together by chemical bonds in a stable association is called which of the following?

molecule

what is made of two or more atoms held together by chemical bonds in a stable association. the atoms may or may not belong to the same element

molecule

elements possessing all eight electrons (two for helium) in their outer energy level are said to be what?

noble gases; inert

hydrophobic interaction

nonpolar regions of a molecule are forced together in order to minimize contact with water molecules

atoms are composed of a central *blank* which is surrounded by orbiting *blank*

nucleus; electrons

where are valence electrons found?

in the outermost energy level only

what is the charge of a hydroxide ion?

-1

which of the following molecules is likely to have the highest specific heat and the highest heat of vaporization?

H2O

the amount of energy required to change 1g of a substance from a liquid to a gas is called which of the following?

heat of vaporization

the relatively weak, but numerous *blank* bonds that form between a water molecule and other molecules (including other water molecules) play a key role in determining the properties of water

hydrogen

which property of water strongly affects the overall shape of many biological molecules, such as protein, and DNA?

hydrophobic exclusion

chemical bonds that form due to the attraction between oppositely charged atoms that have gained or lost electrons are called what bonds?

ionic

electrons that are closer to the nucleus always have which of the following?

less potential energy

covalent bond

sharing of electron

when 1g of sugar is dissolved in 500mL of water, the sugar is called *blank* and water is called the *blank*

solute; solvent

what is the substance that measures how rapidly its individual molecules are moving?

temperature

when the pH of a solution rises by 1 which of the following happens?

the [H+] decreases 10-fold

when the pH of a solution falls by 2

the [H+] increases 100-fold

which of the following is the definition of the heat of vaporization of water?

the amount of energy needed to change 1g of water from a liquid to a gas

if two atoms are joined by a polar covalent bond, the shared electrons will tend to stay closer to the atom with which of the following characteristics?

the higher electronegativity

water is cohesive. Which describes this feature of water molecules?

they are attracted to each other

choose all statements that describes atoms that have unfilled electron shells?

they can form bonds with other atoms; they are chemically reactive; they can form chemical compounds

hydrogen bonds are important for which reasons?

they help maintain the structure of DNA and proteins; they play a key role in determining the properties of water

electrons in outer, unfilled energy levels are known as what?

valence electrons


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