1.2 Molecules and Compounds

Question 1

What is a molecule?

Answer 1

When 2 or more atoms combine. It is the smallest part of a compound that has the compound’s properties.

Question 2

What is a compound?

Answer 2

When 2 or more different elements combine, such as H2O.

Question 3

What are the 4 main macromolecules the cells of the body need to stay alive and functioning properly?

Answer 3

Carbohydrates, lipids, proteins, and nucleic acids.

Question 4

What is a macromolecule?

Answer 4

A large molecule formed when elements and molecules combine. Elements like C, H, and O join to make macromolecules. Each macromolecule is unique and made of different smaller molecules.

Question 5

What are carbohydrates made of?

Answer 5

C, H, O.

Question 6

What doe carbohydrates do?

Answer 6

They store energy and provide structural support.

Question 7

What are some examples of carbohydrates?

Answer 7

Sugar, starches, and cellulose (plant cell walls).

Question 8

What are lipids made of?

Answer 8

C, H, O. Some have N and P.

Question 9

What is the function of lipids?

Answer 9

Help make cell membranes and store energy.

Question 10

What are some examples of lipids?

Answer 10

Fats, steroids, waxes, and phospholipids.

Question 11

What are proteins?

Answer 11

Large chains of amino acids.

Question 12

How many amino acids are there?

Answer 12

There are 20 amino acids.

Question 13

What are nucleic acids?

Answer 13

Long chains of nucleotides.

Question 14

What is the purpose of nucleic acids?

Answer 14

They contain genetic info with instructions for all growth, cell reproduction, and cell processes.

Question 15

What is electronegativity (EN)?

Answer 15

The ability of an atom to attract shared electrons.

Question 16

How does EN change from left to right on the periodic table?

Answer 16

It increases from left to right because there are more protons.

Question 17

What is electron shielding, and how does it affect EN?

Answer 17

When the electron orbitals shield themselves. This decreases EN on the periodic table from top to bottom.

Question 18

What is covalent bonding?

Answer 18

When atoms share electrons to achieve the octet rule.

Question 19

What is ionic bonding?

Answer 19

When atoms are held together by attraction between opposite charges.

Question 20

What makes molecules polar?

Answer 20

Asymmetrical electron distribution around molecule caused by difference in EN. There must be more than one element because atoms of the same element have the same EN.

Geometrical asymmetry: polar bonds don’t necessarily make polar molecules. CO2 is linear, so not polar. There most be a separation of charge around the molecule into positive and negative areas.

Question 21

What won’t dissolve in water?

Answer 21

Non-polar solids.

Question 22

What affects the strength of surface tension in liquids?

Answer 22

The intermolecular forces that pull the molecules of a liquid together.

Question 23

What is a formula?

Answer 23

It gives the number of each kind of atom in a molecule, such as C6 H12 O6 is glucose formula.

Question 24

Why do bonds between atoms in molecules have energy?

Answer 24

Because electrons have energy.

Question 25

Spontaneous reactions occur freely and always release energy.

Answer 25

True.

Question 26

Can H do both ionic and covalent bonding?

Answer 26

Yes, if there is a strong electron acceptor, H becomes an H+ ion. If not, the H shares an electron.

Question 27

What does a line between 2 atoms mean?

Answer 27

It signifies covalent bonding. A single line means 1 shared pair of electrons.

Question 28

What 3 types of paired bonds are there?

Answer 28

Single (HH), double (OO), or triple (NN) covalent bonds.

Question 29

How do the types of covalent bonds differ in strength?

Answer 29

1 < 2 < 3.

Question 30

What are the 2 types of covalent bonding?

Answer 30

Polar and nonpolar.

Question 31

What is nonpolar covalent bonding?

Answer 31

The sharing of electrons is equal between the atoms.

Question 32

What is polar covalent bonding?

Answer 32

The electron is not shared equally - 1 atom attracts the electron greater than the other.

Question 33

Why is methane nonpolar when C is larger and has more protons than H?

Answer 33

Because shape also plays a role in polarity - methane is symmetrical. The polar bonds cancel.

Question 34

In a water molecule…

Answer 34

O atom is more electronegative than the H atoms
O atom has an overall negative charge
H atoms have overall positive charges
Unequal sharing of electrons results in a polar molecule

Question 35

Which statement is NOT true about ionic bonds?

Electrons are completely lost or gained in ion formation.

One atom acts as an electron donor and another atom acts as an electron acceptor.

An ionic bond occurs between positive ions and negative ions.

A salt such as NaCl is formed by an ionic reaction.

An ion has the same number of electrons as a nonionic atom of the same element.

Answer 35

An ion has the same number of electrons as a nonionic atom of the same element.

Question 36

Which statement is NOT true about polar covalent bonds?

The larger atom in a polar bond attracts the electron more strongly than the smaller atom.

Polar covalent bonds are important in the characteristics of water.

The oxygen of a water molecule is electropositive relative to the hydrogen.

Electrons are shared unequally in a polar covalent bond.

Answer 36

The oxygen of a water molecule is electropositive relative to the hydrogen.

Question 37

The electrons are equally shared in ___ and transferred in ___.

Answer 37

Covalent bonding; ionic bonding.

Question 38

Which type of covalent bond is the strongest?

single

double

triple

quadruple

all covalent bonds are equal in strength

Answer 38

Triple.