T2.2 Water

Question 1

Chemical formula for water

Answer 1

H2O

Question 2

Which type of bond is between the atoms in a water molecule?

Answer 2

Covalent bond

Question 3

What is a hydrogen bond

Answer 3

Partly positive hydrogen atoms of one water molecule are attracted to the partially negative oxygen atms of another water molecule.

Question 4

What contributes to the stability of water?

Answer 4

The large number of bonds between all the water molecules

1 water molecule can have hydrogen bonds with 4 more water molecules

Question 5

Which molecules will water dissolve?

Answer 5

Other molecules that have polar covalent bonds and ionic compounds

D

Question 6

How does sodium chloride get transported through blood?

Answer 6

When dissolved, NaCl forms Na+ ions and Cl- ions that is carried in the blood

Question 7

Describe how sodium chloride is dissolved in water

Answer 7

• Water molecules pull the sodium and chloride ions apart, breaking the ionic bond
• This is because the positive hydrogen on water is pulled toward the negative chloride ions, and vice versa for the oxygen and sodium

Question 8

How do amino acids get transported through blood?

Answer 8

• Amino acids have negative and positive charges.
• Because of this, they are soluble in water
• Solubility varies depending on R group
• All are soluble enough to be dissolved in blood plasma

Question 9

How does glucose get transported through blood?

Answer 9

Glucose is polar and is freely soluble in water, thus dissolved and carried in blood plasma

Question 10

How does oxygen get transported through blood?

this one is a little complicated

Answer 10

• nonpolar molecule
• Small size makes it so it is kinddaaa dissolved in water, but blood can only become so saturated with it and only in low concentrations
• Far too little to provide for aerobic cell respiration, so blood uses hemoglobin in red blood cells to provide binding sites for the oxygen
• Increases the capacity of the blood for oxygen transport

Question 11

How do fat molecules get transported through blood?

Answer 11

• entirely nonpolar, larger than oxygen, thus insoluble in water
• Carried inside lipoprotein complexes

Question 12

Lipoprotein complexes

Answer 12

• groups of molecules with a single layer of phosphlipid on the outside
• fats are carried inside.
• Also proteins in the monolayer of phospholipid, hence the name lipoprotein

Question 13

How does cholesterol get transported through blood?

Answer 13

• hydrophobic
• transported with fats in lipoprotein complexes
• In the phospholipid monolayer

Question 14

Cohesion

Answer 14

hydrogen bonding between water molecules makes water stick together

Question 15

Surface tension

Answer 15

cohesion of water molecules along a surface
net effect: stickiness at its surface that causes water to behave as if its surface were covered with a stretch elastic membrane
water has a higher surface tension than most liquids

Question 16

Adhesion

Answer 16

Ability of water molecules to stick to other (polar or charged) surfaces

Question 17

How is adhesion useful in plants

Answer 17

Interaction with cohesion leads to capillary action, which pulls water to tree tops

Question 18

Capillary action

Answer 18

interaction of cohesion and adhesion, allows water to go against gravity without energy use
in xylem of plants

Question 19

High specific heat capacity

Answer 19

• Specific heat - quantity of heat absorbed needed to increase by 1 degree K
• strong hydrogen bonds restrict motion of water molecules
• increase in temperature required to break hydrogen bonds
• takes a lot of energy compared to other compounds

Question 20

Evaportion

Answer 20

Molecule separates from other molecules in a liquid to become a vapor molecule

Question 21

Real world application of high specific heat capacity

Answer 21

Provides for stable internal enviroments and habitats
Sunbathers can absorb a lot of heat without sending their body temperature soaring.

Question 22

Latent heat

Answer 22

Heat needed for evaporation

Question 23

High latent heat of vaporization

Answer 23

Water requires a high input of energy to break hydrogen bonds

Question 24

Real world application of high latent heat

Answer 24

Sweating: use of water as a coolant, heat is taken from tissues of the skin to evaporate, cooling off the body.

Question 25

High boiling point

Answer 25

Highest temp it can reach at it’s liquid state
Water boiling point is high, meaning it can be in a broad range of temperatures (0-100°C)

Question 26

Real world application of high boiling point

Answer 26

Temperature range can be found in most habitats on Earth

Question 27

Why does methane have a much lower melting/boiling point than water?

Answer 27

Methane is non-polar, thus hydrogen bonds do not form between methane molecules. They are more weakly held together, and little energy is need to force the molecules apart.

Question 28

Can you draw 5 water molecules bonding???

Answer 28

you better