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Bio 190 > Ch.2 > Flashcards

Ch.2 Flashcards

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1
Q

Atoms contain three types of particles, positively charge

A
  • Protons
  • Electrons
  • Neutrons
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2
Q

Within an atom’s structure, electrons can be found in cloud like

A

orbitals

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3
Q

Select all of the following that are true about atoms that have partially filled energy shells.

A
  • They can form compounds.

- They tend to share, lose, or gain electrons.

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4
Q

An atom’s atomic number is based on the number of

A

protons

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5
Q

Oxygen has eight protons, eight electrons, and eight neutrons. What is its atomic mass?

A

16

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6
Q

True or false: Electrons are found in the atom’s nucleus.

A

False

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7
Q

A mole of a certain substance has a number of particles equal to

A

12 g of carbon

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8
Q

An electron shell is composed of one or more

A

orbitals

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9
Q

Why is the atomic mass of carbon reported in the periodic table slightly greater than its predicted mass?

A

Because of the presence of a small amount of heavier isotopes

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10
Q

valence ______electrons enable chemical bonds to form among atoms.

A

Unpaired

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11
Q

An atom’s atomic number represents

A

the number of protons.

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12
Q

By mass, the most abundant element in living organisms is

A

oxygen

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13
Q

The chemical formula of glucose is C6H12O6. How many oxygen atoms are in one molecule of glucose?

A
  • 6
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14
Q

The atomic mass numbers reported in the periodic table do not exactly match calculations based on protons and neutrons due to

A

the presence of different isotopes of the same element.

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15
Q

covalent bond is one in which a pair of electrons

A

is shared between two atoms.

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16
Q

What four elements are the most common in living organisms?

A
  • Hydrogen
  • Oxygen
  • Carbon
  • Nitrogen
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17
Q

Why are atoms likely to share electrons?

A

Because they have unfilled outer electron shells.

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18
Q

A new element found on earth has four unpaired electrons in its outer shell. Predict the maximum number of bonds in which the new element can participate.

A

4

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19
Q

A covalent bond in which the atoms share electrons unequally is a(n)

A

polar covalent bond

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20
Q

Atoms share a pair of electrons when they form a(n)

A

covalent bond

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21
Q

Which of the following statements are true of a polar covalent bond?

A
  • The two atoms in the bond share the electrons unequally.

- The atoms in the bond differ in electronegativity.

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22
Q

Which of the following covalent bonds are polar?

A
  • O-H

- N-H

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23
Q

According to the _______ rule, atoms tend to be most stable when their outer shells are filled; this can be accomplished by gaining, losing, or sharing ________.

A
  • Octet,

- electrons

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24
Q

The bond between the hydrogen atom and oxygen atom of separate water molecules is a(n)

A

Hydrogen Bond

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25
Q

Nitrogen has three unpaired electrons in its outer shell. The maximum number of covalent bonds that a nitrogen atom can form with other atoms while still remaining uncharged is

A

3

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26
Q

Van der Waals forces arise when

A

random electron movement creates short-lived attractions.

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27
Q

In a polar covalent bond, the shared electrons are closer to the nucleus of the atom with

A

greater electronegativity.

28
Q

A Na+ion forms when

A

a sodium atom loses an electron.

29
Q

A(n) ______ bond is formed when two atoms of different electronegativities share electrons.

A

polar covalent

30
Q

Which of the following covalent bonds are nonpolar?

A
  • O-O

- H-H

31
Q

An ionic bond forms when a positively charged ion, called a(n) _____, interacts with a negatively charged ion, called a(n) ____

A
  • cation

- anion

32
Q

Van der Waals interactions can form between

A

any atoms

33
Q

Which of the following properties are shared by many chemical reactions that occur in cells?

A
  • They often require a catalyst.
  • They tend to proceed toward equilibrium.
  • They require energy.
34
Q

What type of bond forms when a cation with a positive charge interacts with an anion carrying a negative charge?

A

Ionic

35
Q

Ionic Bond

A
  • Bond between a cation and an anion
36
Q

Hydrogen Bond

A
  • bond between atoms and partial positive and partial negative charge
37
Q

Polar covalent bond

A

Bond in which two atoms share electrons unequally

38
Q

Non-polar covalent bond

A

Bond in which two atoms share electrons equally

39
Q

Chemical reactions require a source of energy and also may require a substance called a(n)_____ that speeds up the reaction rate. Most chemical reactions proceed toward a state called, _____ in which the rate of product formation equals the rate of reaction forms

A
  • enzyme

- equilibrium

40
Q

Which of the following statements describe hydrophilic molecules?

A

They are soluble in water.

41
Q

A(n) ______ bond is formed when two atoms of different electron-negativities share electrons.

A

polar covalent

42
Q

Amphipathic molecules have both

A
  • hydrophobic and hydrophilic
43
Q

The amount of solute (in grams) dissolved in a given volume of solution is the solution

A

concentration

44
Q

Which types of chemical bonds are easily broken in water?

A
  • Ionic bonds

- Hydrogen bonds

45
Q

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)?

A

18

46
Q

When water freezes

A
  • water molecules are packed into a more orderly formation.

- the rate of hydrogen bond breakage slows.

47
Q

Select all of the following that describe hydrophobic molecules.

A
  • They are relatively insoluble in water

- They contain many nonpolar covalent bonds.

48
Q

An amphipathic molecule

A
  • has polar regions.

- has non-polar regions.

49
Q

Water has a high heat of fusion. This means that

A
  • much energy must be withdrawn to cause water to change from a liquid state to solid.
50
Q

The concentration of a liquid is defined as the amount of ______ dissolved in a unit volume of solution.

A
  • solute
51
Q

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)?

A

16

52
Q

Polar covalent O-H bonds in water molecules enable hydrogen bonds to form between water molecules. Which of the following properties of water result from hydrogen bond formation?

A 
Cohesion
Adhesion
Surface tension
High specific heat
High heat of vaporization
53
Q

Which of the following contributes to water’s stability in a liquid state?

A
  • A high heat of fusion

- A high heat of vaporization

54
Q

Pure water can ionize into

A
  • positively charged protons (H+) and negatively charged hydroxide (OH-) ions.
55
Q

High specific heat, surface tension, and cohesion are several properties of water involving

A

hydrogen bonds

56
Q

Sodium hydroxide is a base because when dissolved in water it binds _________ ions that are in solution.

A

hydrogen

57
Q

The pH of a solution is defined as the ______ (base 10) of the hydrogen ion concentration

A

negative logarithm

58
Q

Acidic

A

Contains more H+ than OH- ions

59
Q

Alkaline:

A

Contains more OH- than H+ ions

60
Q

Neutral:

A

Contains equal numbers of OH- and H+ ions

61
Q

Living organisms minimize changes in their internal pH using compounds called

A

buffers

62
Q

When water ionizes, it produces what ions? Select all that apply.

A
  • OH–

- H+

63
Q

Which substance is acidic?

A

stomach fluid

64
Q

The ______ of a solution is the negative base 10 logarithm of the H+concentration of the solution.

A

pH

65
Q

Arrange the following solutions in order ofincreasingproton concentration. The solution with the lowest proton concentration should be placed at the top of the list.

A
  • alkaline
  • Neutral
  • Acidic
66
Q

What type(s) of compound(s) minimize pH fluctuations in the fluids of living organisms?

A
  • buffer

- buffering agent

67
Q

Living organisms minimize changes in their internal pH using compounds called

A

buffers

Bio 190 (21 decks)

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