a1.1.5 - solvent properties of water

Question 1

identify solvent and solutes of a solution

Answer 1

solvent - the liquid in which a solute dissolves
solute - the substance that dissolves in a solvent

Question 2

define solvation

Answer 2

the interaction of a solvent with the dissolved solute

Question 3

explain why water is able to dissolve charged molecules

Answer 3

• water is electrostatically attracted to ions
• the slight positive charge (δ+) of of water hydrogen atom is attracted to the negative charge of an anion
• the slight negative charge (δ-) of of water oxygen atom is attracted to the positive charge of a cation

Question 4

outline the solvation of hydrophilic and hydrophobic subtstances

Answer 4

• hydrophobic means water fearing. because they are not polar or charged, hydrophobic molecules will not dissolve in water. they are insoluble.
• hydrophilic means water loving. because they are polar or charged, hydrophilic molecules will dissolve in water. they are soluble.

Question 5

state an example of the function of a molecule depending on it being hydrophillic and soluble

Answer 5

because they have hydrophilic amino acids, enzymes can dissolve in cytoplasmm where they are used to catalyze chemical reactions in the cell

Question 6

state an example of the function of a molecule depending on it being hydrophobic and insoluble.

Answer 6

because of their hydrophobic tail, phospholipids will form bilayers in water, with the tails not exposed to water.

Question 7

outline the role of water as a medium for metabolism.

Answer 7

cytosol is the liquid part of the cytoplasm, a structure common to all cells. it is composed of about 80 percent water and also contains dissolved salts, fatty acids, sugars, amino acids, and proteins such as enzymes. these substances must be dissolved in water in order to carry out the metabolic processes required to keep the cell alive.

Question 8

describe the role of water as a medium for transport in vascular plants.

Answer 8

• water is used to transport molecules through the body of vascular plants.
• dissolved mineral ions are transported in the xylem from roots to leaves
• dissolved sugars produced in photosynthesis are transported in the phloem from source to sink

Question 9

describe the role of water as a medium for transport in blood.

Answer 9

water is used to transport molecules through the body within the blood. blood plasma transports:
- salt ions
- amino acids
- proteins
- glucose
- waste products of metabolism
- a small amount of dissolved gasses