chemistry

Question 1

what elements make up most of living matter?

Answer 1

carbon, hydrogen, oxygen, & nitrogen

Question 3

trace elements

Answer 3

• essential to life but occur in minute amounts
• common food & water additives
• can cause physiological conditions

Question 4

compounds

Answer 4

elements can combine to form compounds

Question 5

organic compounds

Answer 5

contains both carbon & hydrogen

Question 6

inorganic compounds

Answer 6

does not contain both carbon & hydrogen

Question 7

atomic structure

Answer 7

subatomic particles

• an atom is made up of protons & neutrons
-located in a central nucleus

•a nucleus is surrounded by electrons
-arranged in electron shells (outermost electron shell can hold 8 electrons, first electron shell can hold 2)

Question 9

covalent bonds

Answer 9

• form chemical bonds
-ionic

• 2 atoms share 1+ electrons
•forms molecules

Question 10

protons

Answer 10

+

Question 11

neutrons

Answer 11

=

Question 12

electrons

Answer 12

-

Question 13

nonpolar molecules

Answer 13

when it’s covalently bonded atoms share electrons equally

Question 14

polar molecules

Answer 14

electrons are shared unequally between atoms

Question 15

hydrogen bonds

Answer 15

the charged regions on water molecules are attracted to the oppositely charged regions on nearby molecules

Question 16

cohesion

Answer 16

attraction between molecules of the same substance
(water sticking to water)

Question 17

adhesion

Answer 17

attraction between molecules of different substances
(water sticking to a leaf)

Question 18

acidic & basic conditions

Answer 18

acid - a compound that releases H+ ions in solution

base - 1 accepts H+ ions in a solution

Question 19

pH scale

Answer 19

0 (most acidic) -> 14 (least acidic)
7 is neutral

Question 20

buffer

Answer 20

substances that resist pH change