Discuss your ideas with the people at your group and then write your answer down Vocabulary Solute substance which is dissolved The minority substance in the mixture Aqueous solution solution where ID: 655798
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Slide1
Ch
13: SolutionsSlide2
What do you think the word “solution” means in chemistry (not “solution” as in “answer”)?
Discuss your ideas with the people at your group and then write your answer down.Slide3
Vocabulary
Solute
substance which is
dissolved
The
minority substance in the mixture
Aqueous solution: solution where water is the solvent
Solvent
dissolving
substance
The
majority
substance in the mixtureSlide4
Example: You have a beaker of 1000 mL of
propanol and decide to dissolve some calcium chloride in it. Which is the solute? _______________Which is the solvent? ______________
CaCl
2
PropanolSlide5
Solvents
Most of the time WATER is our solvent
However, there are many important non-water solvents!
Paint Thinner
(Turpentine, C
10H16)Nail Polish remover (Acetone, C3H6
O)Dry cleaning (perchloroethylene,C2Cl4) *a carcinogenSlide6
MIXTURES!
Mixture: Two or more substances mixed together that retain their original properties (in other words, no chemical bonds form between the two or more molecules)Slide7
Types of Mixtures
HOMOGENEOUSthe
same
throughout
HETEROGENEOUS
“different” throughout
SOLUTIONS are always homogeneous!Slide8
Shampoo?
HomogeneousSlide9
Chunky
Picante Salsa?HeterogeneousSlide10
Chex
Mix?HeterogeneousSlide11
Salt water?
HomogeneousSlide12
Summary
Soluble
It
dissolves
. homogeneous- transparent
solutionSoluble liquids are considered miscible Insoluble
It doesn’t dissolve. heterogeneous- can have different “parts”Insoluble liquids are considered
immiscibleSlide13
Remember . . .
Like dissolves like.
Polar substances will dissolve in _________ substances.
Non-polar substances will dissolve in _____________ substances.
Polar
Non-polar
What about ionic substances?Slide14
LABEL EACH MOLECULE AS POLAR COVALENT, NON-POLAR COVALENT or IONIC.
Covalent: 2 or more non-metalsIonic: metal and a non-metalSlide15
Ethanol, C
2
H
6
O
Oil, C
20H
42
POLAR Covalent
NON-POLAR CovalentSlide16
Copper (II) Chloride, CuCl
2
Calcium carbonate, CaCO
3
IONIC
IONICSlide17
Molecular Structures
Citric Acid, C6
H
8
O
6
POLAR CovalentSlide18
Molecular Structures
Acetone, C3
H
6
O
Styrofoam
POLAR, Covalent
WARNING: ACTS NON-POLAR TODAY
NON-POLAR, CovalentSlide19
Intermolecular Forces Review
Intermolecular Forces: the attraction holding 2 or more molecules together
Bonds
: the force holding 2 or more
atoms
together within a moleculeSlide20
Dispersion: (weakest)
found in non-polar molecules
Dipole: (stronger)
attracts polar molecules together
Hydrogen bond: (strongest)
molecules with O-H, N-H, or F-H bonds
Types
of Inter-Molecular Forces (IMF)(see posters for review!)Slide21
Like dissolves Like
Water is polar
This means that a water molecule has both a positive and a negative side (these are the two “poles”)
Water dissolves
ionic
and polar
molecules bestIonic molecules contain positive and negative ionsPolar molecules have positive and negative “sides”Slide22
Like dissolves Like
Polar dissolves polar.
Ethanol and water
Nonpolar
dissolves
nonpolar.Hexane and oil
Nonpolar will NOT dissolve with polaroil (nonpolar) and water (polar) will NOT mixSlide23
Dissolving an ionic solid in H
2O
NaCl (aq)
Na
+
(aq) + Cl
- (aq)The ions will break apart, each ion is attracted to the polar water moleculesSlide24
When molecules dissolve….
Intermolecular forces attract molecules to waterSlide25
Note: when covalent molecules dissolve….
The molecules do NOT break apart into individual atoms or ionsSlide26
Nonpolar Compounds DO NOT dissolve in water
Dipole attractions (between water molecules)
Non-polar substance
(ex: oil)Slide27
Would iodine crystals dissolve in water?
No, iodine is non-polar and water is polarSlide28
Would iodine crystals dissolve in paint thinner?
Yes, iodine is non-polar and paint thinner is non-polarSlide29
Would propanol (C
3H7OH) dissolve in water?
Yes
,
propanol is
polare and water is polarSlide30
Would propanol (C
3H7OH) dissolve in paint thinner (C10H16)?
No
,
propanol is
polar
and paint thinner is non-polarSlide31
Concentration
: The amount of solute for a specified amount of solution. (A common measure of concentration is moles of solute per liter of solution (m/L).)Slide32
MOLARITY!
Moles of solute
Liters of solutionSlide33
You have 8 moles of
HCl
and you pour it into 2 liters of water. What concentration of
HCl
did you produce?
8 moles HCl
2 liters solution
=
4 mol/L OR
4 MSlide34
Which acid would you rather have spill on your arm?
1
M
12
MSlide35
1
M
1 mole/L
would be less concentrated than
12
moles/L!
1
M
12
MSlide36
Find the concentration in moles/L if…
1. 3.75 moles of sodium hydroxide are dissolved in enough water to make a 1.50 Liter solution?2. 0.0014 moles of KNO3
is dissolved in 65 ml?
3. 0.80
moles of KBr are dissolved into 400 ml of solution?
M = 3.75 moles/1.5 L = 2.5 MM = 0.0014 moles/.065 L = .02 M
M = 0.8 moles/0.4 L = 2 MSlide37
4. 225
grams of glucose (C6H12O6) is dissolved to make 3.0 liters of solution.
5.
170 grams of NaNO3 is dissolved to make 5.0 liters of solution.
6. A 500 ml solution contains 249 g of potassium iodide.225 g x
1 mol = 1.25 mol M = 1.25 mol = 0.42 M 180 g 3.0 L
170 g x
1
mol
= 2
mol
M =
2
mol
= 0.4 M 85 g
5.0 L
249 g x
1
mol
= 1.5
mol
M =
1.5
mol
= 3.0 M 166 g 0.5 L