Chapter 12

Heterogeneous Mixture:
compositon not uniform
Homogeneous Mixture
composition uniform throughout
Soluble:
ability of being dissolved
Solution
homogeneous mixture of two or more substances
Solvent
Dissolving medium in a solution(thing its dissolved in)
Solute
substance dissolved in solution(Dissolv-ie)
When a solution is passed through filter paper with the individual components seperate?
no, usual not b/c uniformed throughout
Solutions can happen in gasses, liquids, and solids? T or F
True
Alloys:
solid solutions in which atoms of two or more metals are uniformly mixed

Does changing the proportions of each metal in the alloy create wanted properties?

Take gold, if mixed with copper and silver will it be stronger?

yes

yes

Suspension
particles in solvent so large they settle unless mixture is constantly stirred
Colloids
mixture formed by particles that are perfectly sized(not to big or small)
Do colloidal particles seperate when filtered?
no, b/c small enough
Dispersed phase:
colloidal particles
Dispersing medium:
water
Sol

Solid Dispered in liquid

 

paints, mud

Gel

solid network extending throughout liquid

 

gelatin

Liquid Emulsion

liquid dispered in a liquid

 

milk, mayo

Foam

gas dispered in liquid

 

shaving cream, mousse

Solid Aerosol

solid dispered in gas

 

smoke, auto exhaust

Liquid Aerosol

liquid dispered in gas

 

fog, mist, clouds

Solid Emulsion

liquid dispered in solid

 

cheese, butter

Properties of solutions:

  • Homogeneous
  • particle size(0.01-1 atm);can be atoms, ions, molecules
  • Don’t seperate on own
  • cant be seperated by filtering
  • dont scatter light

Colloid properties:

  • Heterogeneous
  • particle size 1-1000 nm, dispersed; can be aggregates of lrg molecules
  • dont seperate on own
  • cant be seperated by filtration
  • scatter light(Tyndall effect)

Suspension properties:

  • Heterogeneous
  • particle size over 1000 nm, suspended; can be lrg particles or aggregates
  • particles settle on own
  • can be filtered
  • may scatter light, but not transparent

;

Tyndall Effect
when light is scattered by colloidal particles dispersed in a transparent medium
Brownian Motion
when particles are seen moving when light is shone upon them at a right angle
What happens to the negative and positive ions when an ionic compound is dissolved?
seperate from eachother and get surrounded by water molecules
Describe the process in which an ionic compund enables a solution to conduct electric current.
When dissolves, compounds positive and negative ions seperate causing them to be surrounded by the H2O molecules. These ions are then free to move, enabling electric current to pass through
Electrolyte
substance that dissolves in water to give a solution that conducts electric current
Can certain high polar molecular compunds be electrolytes?
yes. look at HCl
A substance that dissolves in water to give a solution that doesnt conduct electric current is called a(n):
nonelectrolyte

An apparatus glows brightly. The solution is:

a)semiconductor

b)electrolyte

c)non electrolyte

b
Ways that affect the rate of dissolution are:

  • increase surface area
  • Stirring
  • heating

Is there a limited amount of a solid solute to solvent combination at a given T that can dissolve?
yes
solution equillibrium:
physical stare in which the opposing processes of dissolution and crystalization of a solute occur at = rates
A solution that contains the max. amnt of dissolved solute is:
saturated solution
A solution that contains less solute than a saturated solution under the exsisting conditions is a(n):
unsaturated solution
Supersaturated solution is when:
a solution contains more dissolved solute than a saturated solution contains under same conditions. So if substance is heated so everythng is dissolved, is then coolde, naturally it will seperate, however w/o disturbance it wont seperate
solubility of substance:
amnt of that substance required to form a saturated solution w/ specific amnt of solvent at a specified temp
“Like dissolves like” means:

similar substances, such as types of bonding, polarity, etc. are capable of dissolving on another.

Rouch general rule. not true for sure!

Why doesthe polarity of the water molecules play such and important role in formation of solutions w. ionic compounds?
b/c the slightly charges particles of water attract ions from ionic compund, therefore causing them to seperate from the crystal(aka dissolving)
Hydration:
is the solution process w/ water as the solvent
What is ment when you say “the ions are hydrated” ?
means that the hyrdated h20 ions are drwing ionic compounds ions away from crystal resultion in dissolution
What are hydrates?
crystalline compunds that incorperate water molecules and maintain same ratios throughout
Whats an immiscible liquid?

Liquids that are not soluble in eachother.

;

look at some PB and salad dressings. Its the seperation!

nonpolar substances with nonpolar liquids are:

a) soluble

b)insoluble

c)mixed but unevenly; not uniform

a. NP have london Disperssion forces =; relativly weak =; molecules from both substances free to intermingle and mix
Liquids that dissolve freely in one another in any proportion are _______.
miscible

Pressure effects solubility very little for:

a)Solids

b)Liquids

c)Gasses

d) Solids ; Liquids

e) Liquids and Gasses

d
Explain process in which P effects solubility.
By ^P it puts stress on the equillibrium, therefore more collisions =; faster rate b/w evaporation and dissolving = equillibrium reached at higher gas solubility
The solubility of a gas in a liquid is directly proportional to the partial P of that gas on the surface of the liquid is____ ____. Which applies to G-L solutions 2 constant T
Henrys Law
That is a perfect example of EFFERVESCENCE in your everyday life?
opening a can of soda. the rapid escape of G from L in which it is dissolved. thats the tssstttt sound when u open a can! this is what causes the ‘fizzy-ness’

Which is easier to predict?

Effects ofSolubility on L and S. or just G?

G
Solvated:
a solute particle that is surrounded by slvent molecules
Enthalpy of solution:
net amnt of E absorbed as heat by the solution when a specific amnt of solute dissolves in solvent

If enthalpy of solution is___ then the rxn is ____.

a) positive; ____

b) negative; ____

a) exo

b) endo

When is E released in enthalpy of solution for gasses?
when a G dissolves in L b/c attraction b/w solute gas and solvent molecules outweighs the E needed to seperate solvent molecules
The ___________ of a solution is a measure of the amnt of solute in a given amnt of solvent or solution
concentration
Molarity is:
the # moles of solute in one L of solution
________ is the concentration of a solution expressed in moles of solute per kilogram of solvent
Molality
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