chapter 2 college bio test

bases can

both take up hydrogen ions and release hydroxide ions

the number of neutrons present in the nucleus of an average atom of any given element is best estimated by

subtracting the number of protons from the mass number

after drinking a great deal of coffee (pH 5) a human's blood buffering system would need to ___ as the coffee was digested to lower the level of acid present in the blood stream

take up H+

the electron arrangement of argon, which has 18 electrons, is

2 in the inner energy shell, 8 in the second energy shell, and 8 in the outer energy cell

the smallest particle of an element that retains the properties of that element

atom

all atoms of the same element have the same

atomic number

a ___ can be defined as a substance that prevents the pH of a solution from changing by either releasing or absorbing H+ in a solution

buffer

Some insects can stride on the surface of water because water

has surface tension

the figure below is depicting the interaction of water molecules with one another, which involves the use of

hydrogen bonds

which of the following explains the events occurring when water boils

hydrogen bonds are broken between neighboring water molecules

the type of bond that would form from the transfer of an electron from one atom to another, shown below, is an ___ bond

ionic

Which one of the following is the smallest unit of matter that has all the properties of an element?

atom

which of the following is not one of the most common elements in living things?

iron

which of the following is not a property of water

it is denser when frozen than when liquid

Baking soda is sometimes used as an antacid. The chemical name for baking soda is Sodium Bicarbonate. What is the bicarbonate doing to help with stomach upset?

it is serving as a buffer to take up excess H+ ions form stomach acid

isotopes of an element differ in their

neutron number

their numbers will vary in isotopes of the same element

neutrons

the subatomic particles that are found in the nucleus of an atom are the

neutrons and protons

isotopes of an atom differ in their

number of electrons

the atomic structure of water satisfies the octet rule by having

oxygen share electrons with two hydrogen atoms

a covalent bond involves the sharing of

pairs of electrons

a water molecule, as shown here, is polar because of

unequal sharing of electrons

what is the steam being given off when water boils

water molecules

which of the following is not a way in which chemical bonds can be formed

splitting electrons

which of the following is not a compound

0-2-

the pH of pure water is ___ because ___

7.0; water dissociates an equal number of H+ ions and OH-

an element has an atomic number of 78. the number of protons and electrons in a neutral atom of the element are

78 protons and 78 electrons

How does a strong acid differ from a weak acid?

A weak acid dissociates only partially in water.

Cola has a pH of 3.5. This means that it has an excess of _______ ions and would be called a(n) ________.

H+, acid

an ionic bond forms when

a negatively charges ion is attracted to one with a positive charge

radioactive isotopes are useful in biological studies becasuse

an organism will take in a molecule with the isotope and use it normally, but the radioactive decay can be detected

an atom that has an electrical charge is called an

ion

glucose, c6h12o6, is best described as a

compound

inside a living cell, which type of bond would be the most stable

covalent

which of the following would not be a valuable use for radioactive isotopes

damaging the DNA of healthy cells

an atom's valence electron shell

determines its chemical reactivity

created when an atom either loses or gains electrons in a reaction, resulting in an overall net charge

ion

their number and arrangement determine which chemical reactions an element can take part in

electrons

a covalent bond occurs when

electrons are shared between two atoms to complete their octets

an atom with a neutral charge has

equal numbers of protons and electrons

which of the following describes how an acid disrupts the chemical bonds of molecules in a cell

the H+ ions can disrupt hydrogen bonds as the slightly negative portion of the molecule is more attracted to H+ ions than to the hydrogen that was part of the bond

the pH scale is a mathematical indicator of the

the concentration of H+ present in a solution

chemical bonds involve

the giving, taking, and sharing of electrons

regarding atoms, identify which statement below is correct

the number and arrangement of electrons in an atom governs its chemical activity

which of the following would be an example of the value of water's heat capacity

living organisms are able to maintain the internal body temperature because the water in their cells resists change in temperature

elements differ from each other in their

physical properties and atomic number

their number in an atom is the atomic number of the element

protons

in the reaction 6CO2 + 6H2O --> C6H12O6 + 6O2 carbon dioxied is of the

reactants

which of the following is a property of acids

release hydrogen ions when dissolved in a liquid

sulfur has an atomic number of 16. what would be the valence number of this element

six

which of the following best describes the structure of how water molecules form and interact

the oxygen atom and hydrogen atoms form a covalent bond with one another to create a stable outer shell of electrons. the electrons are shared unequally resulting in a polar molecule whose slight charges form weak hydrogen bond attractions with other water molecules.

although oregon and south dakota are at similar latitudes, winters in oregon are warmer and summers in oregon are cooler. which of the following might explain these differences between the climate of oregon and the climate of south dakota

the pacific ocean makes oregon tempertures more moderate

which of these does not occur when a sodium atom transfers an electron to a chlorine atom?

there is a mutual sharing of the electrons between the sodium and chlorine atoms

what do lemons, tomatoes, and coffee all have in common chemically

they all produce H+ ions in solution, making them acids

why do cells need buffering agents

to minimize the changes in pH of their internal environment

in what ways are radioactive isotopes potentially harmful

unmonitored release into the environment can make changes in a cell's DNA

the reactivity of an atom depends on the number of

valence electrons

which property of water would help account for how an individual who is exercising and producing excessive heat can maintain a constant body temperature

water has a high heat capacity

which property of water causes sugar to dissolve in coffee

water is a good solvent

of the following examples, which best demonstrates the property of water cohesion

water requires a great deal of heat to reach the point of vaporizing