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Handout 1: States of Matter, Gases, Liquids and Phase transition > 2.2 > Flashcards

Flashcards in 2.2 Deck (24)
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1
Q

What does the properties of ideal solutions depend on?

A

properties depend only on concentration of solute (not identity; eg cation, anion)

2
Q

true or false: more particles = bigger effect

A

true

3
Q

Define molality

m of solute = mol solute/ kilogram of solvent

A

(m) = amount in moles of solute particles (ions, molecules) per kilogram of solvent

4
Q

how to find mole fraction

A

mol fraction A= mol A/ mol A+ mol B+ mol C…

5
Q

Finding weight percentage

A

= mass in grams solute per 100 g solution

6
Q

definition of colligative properties

A

properties of solutions

7
Q

true or false: adding solute to solvent modifies properties of solvent

A

true

8
Q

What do the colligative properties of solution depend on?

A

only on number of solute particles

9
Q

What happens when solute is added to solvent

A
  • vapour pressure lowering
  • boiling point elevation (increases)
  • freezing point depression (drops)
  • osmotic pressure
10
Q

Why does adding solute to solvent, reduce vapor pressure?

A

solute reduces tendency of solvent escaping into vapor phase

so vapor pressure is lower than pure solvent

11
Q

What does Raoult’s law state

A

vapor pressure lowering is proportional to mole fraction of solute

12
Q

What is the effect of vapour pressure to boiling point of solution after non volatile solute has been added

A

boiling point of solution is higher than that of pure solvent at the same pressure; boiling point elevation/ freezing point depression related to molality (amount of solute dissolved)

13
Q

true or false: vapor pressure determines boiling point: lower vapor pressure requires higher temperatures to equal atmospheric pressure

A

true

14
Q

Equation of boiling point elevation (solution first)

A

delta Tb = bp solution - bp solvent
delta Tb = kb * m
Kb= molal boiling point elevation constant (C kg/mol)
m = molality of all solutes in solution

15
Q

true of false: the number of dissolved particles determines size of elevation, as well as what solvent

A

true

16
Q

Express Freezing point depression (solvent first)

A

delta Tf = fp solvent - fp solution

delta Tf = Kf *m

17
Q

true or false: the freezing point of a solution is lower than a pure solvent

A

true

18
Q

why does a solution have a lower freezing point than a pure solvent

A
  • with dissolved solid in saturated solution, rate molecules in solution return to solid is decreased
  • lower temperature is needed for solid state to form
  • solids form when molecules form an orderly pattern (crystals): solute molecules disrupt orderly pattern
19
Q

When does non ideal behavior of ionic solutions increases?

A
  • increased concentration

- increased charge

20
Q

What is osmosis

A

occurs when a pure solvent and a solution is separated by a semi permeable membrane

21
Q

What does the membrane allow?

A

allows passage of solvent only, net flow of solvent molecules into solution occurs

22
Q

direction of movement of osmosis

A

solvent molecules move through membrane form dilute solution into concentrated solution until equilibrium

23
Q

what does the osmotic pressure equal to

A

osmotic pressure (pi) = applied external pressure required to prevent flow of water from solvent to solution (high to low concentration)

24
Q

Equation of osmotic pressure

A

pi = cRT ( concentration mol L-1)