6. Properties of fluids and solutions

Question 1

What is the difference between a mol and molarity/molality?

Answer 1

mol: the amount of a substance (in grams) - just think of the animal moles

molarity/molality: the unit for concentration

rity= moles of solute/L

lity= moles of solute/kg

Question 2

What is Avogadro number for mols?

Answer 2

6.02 x 10^23

Question 3

What are the two processes of solute and water balance involved in osmoregulation?

Answer 3

Diffusion and osmosis

Question 4

Define what diffusion is and what makes particles diffuse easier/harder

Answer 4

The process the tendency for molecules of any substance to spread out evenly into the available space

the hotter the solution is, the more substance will diffuse (crash into each other) becuase of thermal motion (think of making a milo)

Question 5

What’s the fundamental difference between osmosis and diffusion?

Answer 5

osmosis is the movement of water accross a semi-permeable membrane.

diffusion is the movement of molecules to spread out evenly into available space

Question 6

What are the three steps for a solute to cross a membrame. Using proper terminology

Answer 6

1. Solute diffuses from where it is more concentrated to where its less - down its concentration gradient
2. there is passive transport of molecules (ie no energy)
3. after passive transport of molecules, the net diffusion becomes a dynamic equilibrium where solute j

Question 7

What is different about osmosis in terms of water balance compared to diffusion?

Answer 7

osmosis is the process of water diffusing across a semi permeable membrane. diffusion is the movement of solutes

Question 8

What type of permeability do cell membranes have and why is this important?

Answer 8

they are semi permeable memebranes which are only permeable to a solvent (eg water) not solutes (eg ions)

Question 9

Define tonicity and what its determined by

Answer 9

the ability of a solution to cause a cell to gain or lose water. Its determined on water movement

Question 10

What’s the difference between osmolarity and tonicity?

Answer 10

osmolarity is the property of the particle and water in the solution - without regard to the membrane

tonicity is the solution in refernce to a particular membrane and how much solute is on one side compared to the other

Question 11

Define what a) isotonic. B) hypotonic. C) hypertonic is

Answer 11

isonic is where there is no net flow of solutes because the amount of solutes are even (still a flow though)

hypotonic is when the concentration of solutes inside the cell is greater than outside, net movement in, no net movement out. This lysis the cell

hypertonic is when the concentration of solutes outside the cell is greater than inside, causing a dehydrate, shrivelled cell

Question 12

what is the result of a hypotonic solution, isotonic and hypertonic solution around a cell?

Answer 12

look at image

Question 13

what is an acid and a base?

Answer 13

acid: iis any substance that increaes the hydrogen ion concentration of a solution (below pH 7)

base: is any substance that reduces the hydrogen ion concentration of a solution

Question 14

what is a pH buffer? give an example of two that are used

Answer 14

substances that minimise changes in the concnetration of hydrogen an hydroxide ions in a solution (bascially stops it from become acidic or basic)

eg bicarbonte and phosphate buffering in pH homeostais