unit 4

Question 1

oxygen and hydrogen is bonded by–

Answer 1

covalent bonds

Question 2

what do both oxygen and hydrogen share?

Answer 2

both share some electrons

Question 3

water is a what type of molecule?

Answer 3

water is a polar molecule

Question 4

which one is bigger, oxygen atom or hydrogen atom?

Answer 4

oxygen is bigger with 8 protons

Question 5

O (oxygen) is–

Answer 5

“stronger”, pulls most of the electrons towards it

Question 6

O becomes a little–

Answer 6

negative

Question 7

H (hydrogen) is–

Answer 7

“weaker”, loses electrons

Question 8

H becomes a little–

Answer 8

positive

Question 9

what does the unevenness of O and H make the water molecule?

Answer 9

the unevenness makes the water molecule polar

Question 10

how does water stick together?

Answer 10

the positive end of one water molecule attracts the negative end of another water molecule, until all the water molecules are connected

Question 11

what are these types of water connections called?

Answer 11

hydrogen bonds

Question 12

what is a hydrogen bond?

Answer 12

a weak attraction between the slightly negative oxygen of one water molecule, and the slightly positive hydrogen of another water molecule

Question 13

H-bonds are weak alone, but–

Answer 13

strong in high numbers

Question 14

cohesion–

Answer 14

attraction between molecules of the same substance. water-water

Question 15

why is water very cohisive?

Answer 15

because of the H-bonds, molecules hold on to each other very tightly and create high surface tension

Question 16

adhesion–

Answer 16

attraction between molecules of different substances, water loves other substances.

Question 17

what is an example of adhesion?

Answer 17

meniscus in graduated cylinder: water sticks to the glass and “crawls up”

Question 18

capillary action–

Answer 18

when water moves up a thin tube by itself, it’s called capillary action. this is how water moves up in plants

Question 19

how does water move up in plants from the roots to the leaves?

Answer 19

through tubes called xylem (the thinner the tube, the higher the water)

Question 20

true or false: water can move up through small tubes against gravity

Answer 20

true

Question 21

true or false: water is able to absorb large amounts of heat, lakes and oceans stabilize land.

Answer 21

true

Question 22

true or false: water temperatures most substances (good solvent). water inside the cells and body can carry nutrients and waste around.

Answer 22

true

Question 23

true or false: water absorbs heat when it evaporates, organisms can cool off

Answer 23

true

Question 24

how does some insects walk and other things float on water?

Answer 24

because water has high surface tension

Question 25

which is less dense; solid water (ice) or liquid water?

Answer 25

solid water (ice) is less dense

Question 26

what happens to water when it freezes?

Answer 26

it turns into ice, making it float. this prevents rivers, lakes, and oceans from freezing solid

Question 27

the top ice does what to the water?

Answer 27

the top ice insulates the water underneath from the extreme cold