unit 15 solutions, acids, and bases
TRANSCRIPT
![Page 1: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/1.jpg)
1
SolutionsWhy Does Pasta Expand When Cooked?
Why does Lemon Juice sting?
Why Do Salt Grains Dissolve?
![Page 2: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/2.jpg)
2
How Do Solutions Form?
Polar molecules pull polar molecules apart
Water molecules break up the salt crystals
![Page 3: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/3.jpg)
3
Polar Molecules
• Salt Crystal • Water molecules attracting sodium
![Page 4: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/4.jpg)
4
Some DefinitionsA solution is a mixture of 2 or
more substances.
The substance that dissolves the others is the SOLVENT.
The substance that dissolve into the solvent are SOLUTES.
Example: Salt Water
Water = Solvent Salt = Solute
![Page 5: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/5.jpg)
5Solute Solvent Example
Solid Solid Alloys
Bronze is copper and tin
Liquid Liquid Liquor
Ethanol dissolved in water
Gas Liquid Carbonated Water
Carbon Dioxide in Water
Gas Gas Air
Oxygen and other Gasses in Nitrogen
![Page 6: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/6.jpg)
6
DefinitionsSolutions can be classified as
saturated or unsaturated.
An unsaturated solution contains less than the maximum amount of solute.
That means you can dissolve more at that particular temperature
![Page 7: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/7.jpg)
7
DefinitionsSolutions can be classified as
saturated or unsaturated.
A saturated solution contains the maximum quantity of solute that dissolves at that temperature.
If it gets too saturated, crystals will form and drop out of solution.
![Page 8: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/8.jpg)
8
How Temperature Affects Solubility
• More can dissolve in hot fluids than cool fluids.• That is why you heat water to dissolve sugar or
other substances into them.• At cooler temperatures, the crystals will just
drop to the bottom.• If it is saturated and you cool it down, crystals
will drop out of solution.
![Page 9: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/9.jpg)
9
DefinitionsSUPERSATURATED SOLUTIONS
contain more solute than is possible to be dissolved
Supersaturated solutions are unstable and temporary
Any disturbance, including shaking, stirring, or adding more solute will cause it to come out of solution.
![Page 10: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/10.jpg)
10
SupersaturatedSodium Acetate
• One application of a supersaturated solution is the sodium acetate “heat pack.”
• Click on the metal piece inside and it instantly precipitates
![Page 11: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/11.jpg)
11
How do we know ions are present in aqueous solutions?
ELECTROLYTESThey conduct
electricity
HCl, MgCl2, and NaCl are strong electrolytes.
They dissociate completely (or nearly so) into ions.
Aqueous Solutions
![Page 12: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/12.jpg)
12
Aqueous Solutions
Some compounds dissolve in water but do not conduct electricity.
They are called nonelectrolytes.
These are usually covalent compounds, not ionic
Examples include:sugarethanolethylene glycol
Examples include:sugarethanolethylene glycol
![Page 13: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/13.jpg)
13
Electrolytes in the Body
Carry messages to
and from the brain
as electrical signals
Maintain cellular
function.
Make your own
50-70 g sugarOne liter of warm waterPinch of salt200ml of sugar free fruit
squashMix, cool and drink
![Page 14: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/14.jpg)
14
Changing Physical Properties
On adding a solute to a solvent, the properties of the solvent are modified.
• Vapor pressure decreases• Melting point decreases• Boiling point increases• Osmosis is possible (osmotic pressure)
They depend only on the NUMBER of solute particles relative to solvent particles, not on the KIND of solute particles.
![Page 15: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/15.jpg)
15
Change in Freezing Point
The freezing point of a solution is LOWER than that of the pure solvent
Pure water Ethylene glycol
![Page 16: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/16.jpg)
16Change in Freezing Point
Common Applications of Freezing Point Depression
Propylene glycol
Ethylene glycol – deadly to small animals
![Page 17: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/17.jpg)
17
Properties of Acids
• Sour Taste
• Litmus paper turns red
• Reactivity with Metals
![Page 18: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/18.jpg)
18
Properties of Bases
• Bitter Taste
• Litmus paper turns blue
• Slippery Feel
• Corrosive
![Page 19: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/19.jpg)
19
Definitions:
An acid is a substance that increases the H+ (or H3O+) concentration in an aqueous solution. Also known as proton donors.
HCl + H2O
A base is a substance that increases the OH- concentrationin an aqueous solution. Also known as proton acceptors.
H+ + H2O + Cl-
H3O+ + Cl-
NaOH(s) Na+ + OH-
![Page 21: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/21.jpg)
21
Why is Sea Water Basic?
Alkaline substances such as limestone dissolve from rocks, head down rivers, and are deposited
in the sea
Coral, clams, snails, and others make their shells from the calcium dissolved in sea water
![Page 22: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/22.jpg)
22
Ocean AcidificationThe pH of the ocean is becoming more acidic with global warming.
That is because more CO2 is dissolving into the ocean as more if released by humans into the atmosphere
This makes it more difficult for sea creates with calcium shells to survive
Their calcium shells dissolve in the acidic water
Coral reefs are being destroyed and the ocean ecosystems affected.
![Page 23: Unit 15 Solutions, Acids, and Bases](https://reader038.vdocuments.mx/reader038/viewer/2022103017/556e692bd8b42a6a248b50a5/html5/thumbnails/23.jpg)
23
Acid/Base reactions (neutralization):
Produce water and a salt (and sometimes carbon dioxide).
Hint: concentrate on the water first. Remember, water has the formula HOH.
Complete and balance the following:
HCl + KOH
HCl + Ca(OH)2
H2O + KCl
2
Require equal numbers
2HOH + CaCl2