Chapter 1-4 Exam Study guide

Question 1

Isotopes

Answer 1

– One of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus a differing atomic mass.

Question 2

Covalent Bonds

Answer 2

The sharing of a pair of valence electrons by two atoms. Two or more atoms held together by covalent bonds constitute a molecule.

Question 3

Polar Covalent

Answer 3

When one atom is bonded to a more electronegative atom, the electrons of the bond are not shared equally. Such bonds vary their polarity, depending on the relative electronegetivity of the two atoms. An example of this is the bonds between the oxygen and hydrogen atoms of a water molecule.

Question 4

Non-polar Covalent Bond

Answer 4

the covalent bond between two atoms of the same element that share the electrons equally because of the same electronegativity. They have a tug-of-war.

Question 5

Ion

Answer 5

a charged atom (or molecule)

Question 6

Ionic Bond

Answer 6

When cations and anions attract each other because of their opposite charges.

Question 7

Hydrogen Bond

Answer 7

The noncovalent attraction between a hydrogen and an electronegative atom. In living cells, the electronegative partner are usually oxygen or nitrogen atoms.

Question 8

Van der Waals Interactions

Answer 8

Weak attractions between molecules or parts of molecules that result from transient local partial charges. These occur only when atoms and molecules are very close together; when many of these interactions occur simultaneously, they can be powerful. An example is the toes of gecko’s. The hundreds of tiny hairs, with multiple projections at each hairs tip increase surface area, there is an individual Van der Waals interaction between each hair tip and the surface of a wall, allowing the geicko to wall up a wall.

Question 9

cohesion

Answer 9

the hydrogen bonds hold the substance together, a phenomenon called

Question 10

Adhesion

Answer 10

the clinging of one substance to another. Adhesion of water to cell walls by hydrogen bonds helps counter the downward pull of gravity.

Question 11

Temperature

Answer 11

a measure of heat intensity that represents the average kinetic energy of the molecules, regardless of volume.

Question 12

Specific Heat

Answer 12

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 can be thought of as a measure of how well a substance resists changing its temperature when it absorbs or releases heat. Think about the temperature of water at say Ocean City at the beginning or Winter, or Summer.