Deck 2: Lifes Chemical Basis

Question 1

How much mercury can the average human safely consume per day?

A) 1 microgram.
B) 3 micrograms.
C) 7 micrograms.
D) 10 micrograms.
E) 100 micrograms.

Answer 1

C

Question 2

The atomic number refers to the

A) mass of an atom.
B) number of protons in an atom.
C) number of both protons and neutrons in an atom.
D) number of neutrons in an atom.
E) number of electrons in an atom.

Answer 2

B

Question 3

The radioactive decay of ¹⁴C produces

A) carbon 12.
B) carbon 13.
C) more carbon 14.
D) nitrogen 14.
E) oxygen 14.

Answer 3

D

Question 4

Toxic elements such as mercury are found in the human body because

A) of contamination from the environment.
B) trace amounts of these elements have vital biological functions.
C) they are needed to kill bacteria.
D) they may be ingested with food but inactivated by cells.
E) in small amounts they are biologically inactive and tolerated by cells.

Question 5

Which components of an atom do not have a charge? I.
Electrons
II)
Protons
III)
Neutrons

A) I only
B) II only
C) III only
D) I and II
E) II and III

Question 6

Tracers are elements that

A) are used in minute amounts in plants.
B) can be monitored through biochemical reactions.
C) must be inert.
D) have an unbalanced electrical charge.
E) must have a stable nucleus.

Question 7

Which components of an atom have negative charges? I.
Electrons
II)
Protons
III)
Neutrons

A) I only
B) II only
C) III only
D) I and II
E) II and III

Question 8

Which of the following is false concerning the atom in the figure?

A) The number of protons and the number of electrons are equal.
B) It has an atomic mass of 4.
C) Electrons are moving around the nucleus.
D) It has an atomic number of 2.
E) The number of electrons exceeds the number of protons.

Question 9

Which statement concerning radioisotope ¹⁴C is false?

A) It can be substituted for ¹²C in glucose and the body will still be able to use the compound.
B) It has a different number of protons than ¹²C.
C) It has more neutrons than ¹²C.
D) It behaves the same chemically as ¹²C.
E) It has six carbons and eight neutrons.

Question 10

Radioactive isotopes have

A) excess electrons.
B) excess protons.
C) excess neutrons.
D) insufficient neutrons.
E) insufficient protons.

Question 11

The atomic mass (mass number) of an atom is determined by the combined masses of its

A) neutrons and protons.
B) neutrons and electrons.
C) protons and electrons.
D) protons, neutrons, and electrons.
E) neutrons, nucleus, and electrons.

Question 12

Isotopes of atoms

A) are electrically unbalanced.
B) behave the same chemically and physically but differ biologically from other isotopes.
C) are the same physically and biologically but differ from other isotopes chemically.
D) have the same number of protons but a different number of neutrons.
E) are produced when atoms lose electrons.

Question 13

Argon has 18 protons.How many electrons are in its third energy level?

A) 2
B) 4
C) 6
D) 8
E) 10

Question 14

Which of the following statements is NOT true?

A) All isotopes of an element have the same number of electrons.
B) All isotopes of an element have the same number of protons.
C) All isotopes of an element have the same number of neutrons.
D) We refer to isotopes by mass number.
E) ¹²C and ¹³C are isotopes.

Question 15

The nucleus of an atom contains

A) neutrons and protons.
B) neutrons and electrons.
C) protons and electrons.
D) protons only.
E) neutrons only.

Question 16

Which is NOT an element?

A) water
B) oxygen
C) carbon
D) chlorine
E) hydrogen

Question 17

In the chemical shorthand ¹⁴C, the 14 represents the number of

A) excess neutrons.
B) protons plus neutrons.
C) electrons.
D) protons plus electrons.
E) radioactive particles.

Question 18

Which is the smallest unit of an element that retains the properties of the element?

A) atom
B) compound
C) ion
D) molecule
E) mixture

Question 19

The subatomic particle(s) with a negative charge is(are)

A) the neutron.
B) the proton.
C) the electron.
D) both the neutron and proton.
E) both the proton and electron.

Question 20

In a chemical equation, the chemicals to the left of the arrow are

A) products.
B) in greater abundance.
C) at higher energy levels.
D) reactants.
E) all of these.

Question 21

Which statement is false?

A) A molecule is made of at least two atoms.
B) Compounds are made of elements.
C) Two atoms of oxygen make a molecule of oxygen.
D) Proportions of elements in compounds vary according to their source in nature.
E) Elements are found in compounds and molecules.

Question 22

Which of these statements is false concerning covalent bonds?

A) Atoms share electrons.
B) Molecules may possess many covalent bonds.
C) Water contains polar covalent bonds.
D) Covalent bonds may be "double bonds."
E) In polar covalent bonds, electrons are shared equally.

Question 23

The solvent, cohesive, and temperature stabilization properties of water are due to its

A) ability to promote hydrophilic interactions.
B) ionic bonds.
C) hydrogen bonds.
D) ability to promote hydrophobic interactions.
E) nonpolar nature.

Question 24

In ____ bonds, both atoms exert the same pull on shared electrons.

A) nonpolar covalent
B) polar covalent
C) double covalent
D) triple covalent
E) coordinate covalent

Question 25

The most likely reason that glucose dissolves in water is that it is

A) an ionic compound.
B) a polysaccharide.
C) polar and forms many hydrogen bonds with the water molecules.
D) a very unstable molecule.
E) highly nonpolar.

Question 26

Which statement is NOT true?

A) Electrons closest to the nucleus are at the lowest energy level.
B) No more than two electrons can occupy a single orbital.
C) Electrons are unable to move out of the assigned orbital space.
D) The innermost orbital holds two electrons.
E) At the second energy level there are four possible orbitals with a total of eight electrons.

Question 27

Carbon dioxide is an example of a(n)

A) atom.
B) ion.
C) compound.
D) mixture.
E) element.

Question 28

"Acidic" is an appropriate description for all EXCEPT which one of the following?

A) excess hydrogen ions
B) the contents of the stomach
C) magnesium hydroxide
D) HCl
E) a pH less than 7

Question 29

Water is important to the interactions of biological molecules because it

A) promotes hydrophobic and hydrophilic interactions.
B) stabilizes temperature.
C) is an excellent solvent for polar and ionic substances.
D) has strong cohesive properties.
E) does all of these.

Question 30

The column of water extending in tubes from plant roots to leaves is maintained by

A) cohesion among water molecules.
B) ionic bonds.
C) covalent bonds.
D) hydrophobic interactions.
E) hydrophilic interactions.

Question 31

Sodium chloride (KCl) in water can be described by any EXCEPT which of the following?

A) K⁺ and Cl^-form
B) a solute
C) ionized
D) forms hydrophobic interactions
E) dissolved

Question 32

Which of the following is NOT accurate concerning ionization?

A) When one atom loses electrons, another must gain electrons.
B) When an atom loses an electron, it becomes negatively charged.
C) Ionic bonds form between ionized atoms.
D) In the compound NaCl, Na loses an electron to become positive.
E) In an ion, the number of protons and electrons is unequal.

Question 33

A molecule is

A) a combination of two or more atoms.
B) a mixture of atoms.
C) electrically charged.
D) a carrier of one or more extra neutrons.
E) none of these.

Question 34

A salt will dissolve in water to form

A) acids.
B) hydrogen bonds.
C) ions other than H⁺ and OH^-.
D) bases.
E) buffers.

Question 35

Blood pH is kept near a value of 7.3 - 7.5 because of

A) salts.
B) buffers.
C) acids.
D) bases.
E) water.

Question 36

A solution with a pH of 9 has how many times fewer hydrogen ions than a solution with a pH of 6?

A) 2
B) 4
C) 10
D) 100
E) 1,000

Question 37

A hydrogen bond is a(n)

A) sharing of a pair of electrons between a hydrogen and an oxygen nucleus.
B) sharing of a pair of electrons between a hydrogen nucleus and either an oxygen or a nitrogen nucleus.
C) attractive force between a hydrogen atom and either an oxygen or a nitrogen atom that are in other molecules or within the same molecule.
D) covalent bond between two hydrogen atoms.
E) covalent bond between a hydrogen atom and either an oxygen atom or a nitrogen atom.

Question 38

The dots in the figure represent a(n)

A) covalent bond.
B) ionic bond.
C) hydrogen bond.
D) polar covalent bond.
E) hydrophobic interaction.

Question 39

The bond in table salt (NaCl) is

A) polar.
B) ionic.
C) covalent.
D) double.
E) nonpolar.

Question 40

Nitrogen, with an atomic number of 7, has ____ electrons in the first energy level and ____ electrons in the second energy level.

A) 1; 6
B) 2; 5
C) 3; 4
D) 4; 3
E) 5; 2

Question 41

Classification.The following are types of chemical bonds.Answer the questions below by matching the descriptions with the most appropriate bond type.
a.hydrogen
b.ionic
c.covalent
d.polar covalent
e.double bond
the bond between the atoms of table salt (NaCl)

Question 42

An atom with more protons than electrons is called a(n) __________.

Question 43

Classification.The following are types of chemical bonds.Answer the questions below by matching the descriptions with the most appropriate bond type.
a.hydrogen
b.ionic
c.covalent
d.polar covalent
e.double bond
the bond between the oxygen atoms of oxygen gas (O₂)

Question 44

Classification.The following are types of chemical bonds.Answer the questions below by matching the descriptions with the most appropriate bond type.
a.hydrogen
b.ionic
c.covalent
d.polar covalent
e.double bond
the bond that breaks when salts dissolve in water

Question 45

MATCHING
Classification.The various energy levels in an atom of magnesium (
) have different numbers of electrons.Use the numbers below to answer the following questions.
a.1
b.2
c.3
d.6
e.8
number of electrons in the first energy level

Question 46

MATCHING
Classification.The various energy levels in an atom of magnesium (
) have different numbers of electrons.Use the numbers below to answer the following questions.
a.1
b.2
c.3
d.6
e.8
number of electrons in the second energy level

Question 47

C¹⁴ is a radioactive isotope, and it turns into _____________ when it decays.

Question 48

Classification.The following are types of chemical bonds.Answer the questions below by matching the descriptions with the most appropriate bond type.
a.hydrogen
b.ionic
c.covalent
d.polar covalent
e.double bond
Two pairs of electrons shared between two atoms is called a __________.

Question 49

Classification.The following are types of chemical bonds.Answer the questions below by matching the descriptions with the most appropriate bond type.
a.hydrogen
b.ionic
c.covalent
d.polar covalent
e.double bond
Water surface tension is caused by __________ bonds.

Question 50

Classification.The following are types of chemical bonds.Answer the questions below by matching the descriptions with the most appropriate bond type.
a.hydrogen
b.ionic
c.covalent
d.polar covalent
e.double bond
a bond in which connected atoms share electrons

Question 51

Classification.The following are types of chemical bonds.Answer the questions below by matching the descriptions with the most appropriate bond type.
a.hydrogen
b.ionic
c.covalent
d.polar covalent
e.double bond
the bond type holding several molecules of water together

Question 52

MATCHING
Classification.The various energy levels in an atom of magnesium (
) have different numbers of electrons.Use the numbers below to answer the following questions.
a.1
b.2
c.3
d.6
e.8
number of electrons in the third energy level

Question 53

The ability of a solution to resist changes in pH depends on its ______________.