1. Chapter 22
Solutions

2. What is a solution?
A solution is a mixture that has the same composition, color, density and even taste throughout
The most common solutions are liquids and have water in them, but not all are
To describe a solution, you might say that one substance is dissolved in another

3. Parts of a solution
The substance being dissolved is the solute, and it is always in lower amounts that the solvent
The solvent is the substance that does the dissolving and is always in higher amounts than the solute
Water is known as the “Universal Solvent” because it can dissolve many things

4. Non liquid Solutions
Solutions can be solid, like bronze, which is a mixture of both copper and tin. Brass is a mixture of copper and zinc.
Solid solutions are known as alloys
Air is a gaseous solution that is a mixture of Nitrogen, oxygen, carbon dioxide, hydrogen and others.

5. Identify the solvent and solute in each
Kool Aid
Ocean water
Bronze
Air
Carbonated soft drink

6. Water is Polar
Water is a special molecule that can dissolve just about everything
The trick is, like dissolves like
Water is a polar liquid, so it can dissolve polar solids such as salt
Something is considered polar if it has a positive area and a negative area in the same molecule

7. Polar Molecules
Water
Table Salt and Water

8. How does sugar dissolve in water
Step 1: Water clusters around sugar molecules, negative ends attracted to positive
Step 2: Water molecules pull sugar molecules into solution
Step 3: Water and sugar molecules mix evenly, forming a solution

9. More Dissolving Gases can dissolve in liquids
Liquids can also dissolve in liquids
Making solid solutions, or alloys is more complicated, you must melt the solids down and mix them so they will remain mixed when cooled

10. Rate of Dissolving
When one thing dissolves in another, it does so at a constant rate
You can increase the dissolving rate by doing three things
Stirring- brings more solvent into contact with solute
Decreasing crystal size (grinding)- gives solvent more surface area to dissolve
Increase temperature- makes particles move faster and mix easily

12. Solubility and Concentration
How much can dissolve?
Solubility is the maximum amount of solute that can be dissolved in a solvent at a certain temperature
Concentration depends on how much solute is dissolved in the solvent
A solution with more solute than another in the solvent is considered more “concentrated”
Example orange drink is 10 % juice, where orange juice is 100 % juice– the juice is more concentrated in one than the other

13. Saturated vs Unsaturated Solutions
A saturated solution is one that holds all the solute that it can at a certain temperature.
In an unsaturated solution, more solute can be dissolved in the solvent at a certain temperature

14. Solubility Curves
You can use these to determine how much of a solute can dissolve in a given solvent at a certain temperature

15. Supersaturated Solutions
Unstable solution that have more solute dissolved in the solvent than they should
You can supersaturate a solution by heating it, forcing more solute to dissolve, then letting it cool
As it cools, some of the solute falls out of solution
You can make rock candy using a supersaturated solution of sugar and water

16. Solubility of Gases
You can increase the amount of a gas dissolving in a liquid by INCREASING the pressure or DECREASING the temperature
More carbon dioxide gas is dissolved in a cold soft drink than a warm one, that’s why sodas get “flat” as they warm up

17. Particles in Solution
Pure water is a poor conductor of electricity. In order for water to conduct electricity well, you have to add ions to it.
Solutions of ions that conduct electricity well are called electrolytes

18. Effects of Solute Particles
Adding antifreeze to the water in your car radiator both lower the freezing point of the water AND raise the boiling point of water
Meaning, that with the antifreeze, the water in your radiator won’t freeze or boil as easily
Some animals such as polar fish and caribou have a natural antifreeze in their bodies that keep them from freezing in cold temperatures

19. When Water Won’t Work Water cannot dissolve all substances.
If a substance is non-polar, meaning it has even charges all the way through and no negative and positive ends, the water cannot dissolve it
Some substances are both polar and non-polar because part of the molecule is charged, and the other part is not. Ethanol is an example.

20. Nonpolar Solvents
Goo gone, lighter fluid, dry cleaning solution are all examples of nonpolar solvents and can dissolve things that water can’t.
Nonpolar solvents are often toxic and flammable
They can produce harmful vapor

21. The Chemistry of Soap
Non polar ends of soap attach to dirt and oil and dissolve it
Polar ends of soap mix with water and all is washed away
Soap works because it is BOTH Polar and Non-polar

22. Acids, Bases and Salts
Chapter 23

23. Acids
Acids can be harmful or they can be safe, depending on the specific one
What they all have in common, is that in solution, they all release H+, hydrogen, or hydronium ions into water
Acids have a sour taste
Some are corrosive and can react strongly with certain metals
Acids also react with indicators (a substance used to identify acids and bases)
Litmus paper, for example, changes red in presence of an acid

24. Common Acids Hydrochloric Acid HCl – gastric juices (stomach acid)
Ascorbic Acid – vitamin C
Citric Acid– found in citrus fruits
Carbonic Acid- carbonated drinks
Sulfuric Acid– battery acid

25. Bases In solutions, bases release OH- or hydroxide ions into water
Bases are the opposite of acids
They are smooth and slippery
They have a bitter taste
Strong bases are corrosive and can burn
Litmus paper turns blue in bases

26. Common Bases Soaps Cleaning supplies Bleach Milk of Magnesia
Alka Seltzer and Tums (antacids)

27. Ammonia is Special Ammonia is a strong base used as a cleaner
It does not form hydroxide ions in solution
Do not use ammonia with anything containing chlorine like bleach
If you mix the two together, it makes a poisonous gas that is fatal

28. Dissociation
When acids and bases dissolve in water, the ions are attracted to the water and in some cases, they are mixed completely in the water
This is called dissociation
When acids dissociate, they release H+ ions in water (hydronium)
When bases dissociate, they release OH- ions in water (hydroxide)

29. Strong and Weak Acids and Bases
The strength of an acid or base depends on the number of ions dissociated in solution
A strong acid or base has many ions in solution, dissociates completely
A weak acid or base has few ions in solution, does not dissociate completely
Ions meaning H+ for acids and OH- for bases

30. pH of Solutions
pH of a solution is the measure of the concentration of H+ ions in solution
The pH scale ranges from 0 to 14
An acid has a pH below 7
A base has a pH above 7
7 is neutral, pure water is an example
You can measure pH using a pH meter or indicator pH paper, which turns a certain color for each pH value

31. pH Scale

32. Blood pH
In order for blood to function properly, it must have a pH between 7 and 7.8
Many enzymes cannot work outside this range
How is it that you can eat acidic foods and not change your blood pH?
Your blood contains buffers, solutions containing ions that react with acids and bases to minimize changes in pH

33. Neutralization
Antacids such as Tums or Alka Seltzer produce what is called neutralization in your stomach
This is because too much acid can cause discomfort
Neutralization is a chemical reaction between an acid and a base which produces water
Remaining ions in a solution react to form salts

34. Salts Salts are essential for healthy life
Most salts contain a positive metal ion and an ion with a negative charge
Ammonium salts contain the ammonium ion instead of a metal