Chapter 2 - Chemistry and Molecules of Life

Question 1

What is matter?

Answer 1

anything that takes up space/has mass

Question 2

What are elements?

Answer 2

pure substances that cannot be broken down

Question 3

What are compounds?

Answer 3

elements combined in a fixed ratio

Question 4

What are atoms?

Answer 4

units that cannot be broken down, what elements consist of

Question 5

Nucleus

Answer 5

dense core

Question 6

Protons

Answer 6

positive charge

Question 7

Electrons

Answer 7

negative charge

Question 8

Neutrons

Answer 8

electrically uncharged/neutral

Question 9

Atomic Number

Answer 9

equals the number of protons

Question 10

Atomic Mass

Answer 10

number of protons plus number of neutrons

Question 11

What is an isotope?

Answer 11

alternative mass forms of an element

• same number of protons and electrons
• different number of neutrons

Question 12

What is an ion?

Answer 12

electrically charged atom

Question 13

Ionic Bonds

Answer 13

attraction of opposite charges holding atoms together

• transfer of electrons from one atom to another
• -> become ions because the atoms are no longer neutral

Question 14

Arrangement of Electrons

Answer 14

• constantly moving
• 2 on inner shell, 8 on outer (valence) shell
• filling outer shell=not reactive

Question 15

Ionic Bonds

Answer 15

attraction of opposite charges hold atoms together

• transfer of 1 or more electrons from one atom to another
• strong

Question 16

Covalent Bonds

Answer 16

electrons shared rather than transferred

• bonds hold atoms together forming molecules
• strong

Question 17

Double Covalent Bond

Answer 17

sharing two pairs of electrons

more bonds = stronger

Question 18

Reactant

Answer 18

molecules that participate in reactions

Question 19

products

Answer 19

molecules formed by reactions

Question 20

What kind of bond does water have?

Answer 20

Covalent Bond

Question 21

What is a polar covalent bond?

Answer 21

oxygen is more electronegative than hydrogen so it spends more time with the electrons, giving the water molecule a slightly more negative charge

Question 22

Hydrogen bond

Answer 22

slightly positive hydrogen atoms are attracted to slightly negative oxygen atom in water molecule

• weak bond, but impressive
• easily broken which leads to liquid water
• -> results in water having a higher resistance to temp change

Question 23

Cohesion

Answer 23

tendency of same type of molecules to stick together (ex. water rising from roots of plants to leaves against gravity)

Question 24

Surface Tension

Answer 24

cumulative strength of hydrogen bonds prevent water surface from breaking (ex. insect walking on water)

Question 25

hydrophilic

Answer 25

molecules attracted to water

Question 26

hydrophobic

Answer 26

molecules not attracted to water

Question 27

What is true of an uncharged atom?

Answer 27

of protons = # of electrons

Question 28

polar molecule

Answer 28

unevenly charged

Question 29

temperature vs. heat

Answer 29

temp: intensity of heat
heat: amount of energy associated with movement of atoms/molecules

Question 30

What happens when water cools?

Answer 30

hydrogen bonds form, releasing heat

Question 31

Solution

Answer 31

liquid consisting of a homogeneous mix on 2+ substances

Question 32

Solvent

Answer 32

dissolving agent

Question 33

Solute

Answer 33

substance that is dissolved

Question 34

What is an acid?

Answer 34

chemical compound that releases hydrogen ions to a solution

Question 35

What is a base?

Answer 35

compound that accepts hydrogen ions and removes it from solution

Question 36

What is the pH scale?

Answer 36

describes acidity, measures hydrogen ion concentration in solution (ranges from 0 to 14, most acidic to most basic)

Question 37

Carbon

Answer 37

-abundant
-versatile building block
–>long chain of carbon atoms are “backbone” of most molecules
(Organic: molecules with chains of carbon atoms, Inorganic: molecules with no carbon atoms)