solutions & solubility chemistry mrs. stoops general chapter16 accelerated chapter 13
TRANSCRIPT
Solutions & Solubility
ChemistryMrs. Stoops
General Chapter16Accelerated Chapter 13
Parts of a Solution
What is being
dissolved
What is DOING the dissolving
Miscible Immiscible
Miscible and Immiscible describe whether two liquids will mix with each other or not
Factors that Affect Solution Formation
Stirring Particle Size Temperature
Solubility - saturatedAbility to be dissolved
Solubility - Supersaturated
Highly unstable
Saturated solution that was heated and more solute was added. Then the solution was cooled slowly
Addition of one piece can cause crystals to form (shown above)
Factors affecting solubility
Pressure
Temperature
Gases only
The type of substance – solute and
solvent interaction
Solubility Graph
Amount that can
dissolve
Above the line
On the line
Below the line
There is extra
Completely
dissolves
More could dissolve
What is solubility of KNO3 at 50 C?
80 g per 100 mL H2OIf the temperature
changes from 90 C to 50 C, what happens to NH4Cl?20 g falls out of
solution
Units of Concentration
• Need to be more specific than “a lot” or “a little” • Describes how much solute is dissolved in a
solution• Examples include:
– Ppm– Ppb– Molarity– % by mass– % by volume– Molality– And others
Molarity
• Describes amount of solute dissolved in a specific amount of solution
• Units are molar (or molarity)• Abbreviated M• Can be whole numbers or decimals
solution of literssolute of moles
Molarity
Molarity Examples
• Determine the molarity of a solution made by dissolving 15 gKCl into 25 mL of water
KCl mol 0.20KCl 74gKCl 1mol
KCl 15g Part 1
Part 2
M 8.00.025L
KCl 0.20mol
Molarity Examples
• What mass of MgCl2 is needed to make a 250 mL solution that has a molarity of 0.15M?
0.250LMgCl moles ?
0.15M 2Part 1
0.0375 mol MgCl2
Part 2
22
22 MgCl 3.53g
MgCl 1molMgCl 94g
MgCl 0.0375mol
% by Mass
• Compares the amount of solute (or solvent) in a certain amount of solution
• By mass (so grams usually)
100solution of mass total
component of mass%mass
Example
• If the percent (mass/mass) for a solute is 4 % and the mass of the solution is 200 g, what is the mass of solute in the solution?
100solution of mass total
solute of massmass %
g 82000.04
% by Volume
• Same as % by mass except uses volume• Usually mL or L
100solution of volume total
component of volume%volume
Example
If the volume of solute is 6.0 mL and volume of solution is 300.0 mL, what is the solute’s percent by volume?
% 2.0 100mL 300.0
mL 6.0volume %