Fake Gold and Green Skin

More fun info based on our studies of elements, chemical reactions, acids and salts so far this year…

HowStuffWorks “Why does fake gold turn your skin green?”: “When you buy a cheap, fake gold ring, it’s likely made of mostly copper. When you perspire, the metals in the ring react with the acid in your sweat to form salts, which are green. These acids are essentially causing the copper to corrode on the surface of the metal, which forms a salt compound of the metal. These salts are absorbed into the skin and the result is a decidedly green digit. This is nothing to be worried about; it’s not a metal allergy you’re suffering from. It simply means that the gold ring you thought was real is really just a cheap imitation. Metal allergies cause redness and swelling, not a dull green color. Another way to spot fake gold is that it can rust in high humidity or over time. “

The world is much more interesting when you know a little background information!

Ch. 7 Review

Here is the Pop-Review Quiz we did in class today (click).

Remember, our 50 POINT test on Chapter 7 is tomorrow!

QUESTION 1
Which is not a type of mixture?
Solution
Colloid
Acid
Suspension

QUESTION 2
Sugar water is an example of a:
suspension
solution
solute
colloid

QUESTION 3
Ammonia is an example of a(n):
acid
base
salt
antacid

QUESTION 4
Acids produce __________ in water.
hydroxide ions
pH scale
solute
hydrogen ions

QUESTION 5
HCl is a common ________.
acid
base
salt
solution

QUESTION 6
Milk is a good example of which type of mixture?
acid
solution
base
colloid
suspension

QUESTION 7
A base produces ____________ in water.
hydroxide ions
salts
hydrogen
hydrogen ions

QUESTION 8
The names of acids normally end in _______.
-ide
-ice
-ixe
-ic

QUESTION 9
When acids react with magnesium, zinc and iron, _________ is produced.
salt
hydrogen gas
hydrogen ions
hydroxide ions

QUESTION 10
Salt is any compound that is made from the __________ of an acid with a base.
solubility
solution
reaction
neutralization
precipitation

Chapter 7 Review Podcasts

Here are the five review podcasts to help you prepare for our TEST on chapter 7 this Wednesday…

Section 7.1:
Listen!

Section 7.2:
Listen!

Section 7.3:
Listen!

Section 7.4:
Listen!

Chapter 7 Wrap-Up:
Listen!

Let me know if you have any questions!

7.4: Acids and Bases in Solution

Here is the note sheet covering section 7.4 from today’s class (click).

1. What is a hydrogen ion?
2. What is the key to the reaction of acids?
3. Please give another definition of acids based on what we’ve learned about hydrogen ions.
4. What are many bases made from?
5. Describe the hydroxide ion
6. Please give another definition of bases based on what we’ve learned about hydroxide ions.
7. To what does the strength of an acid or base refer?
8. How does a strong acid differ from a weak acid?
9. What are some examples of strong acids?
10. What is an example of a strong base?
11. What is the pH scale?
12. What does a low and high pH tell you?
13. What is a “salt”?
14. What happens in a neutralization reaction?

7.3 Describing Acids and Bases

Here is the notesheet from today’s class on section 7.3 on acids and bases (click).

Remember, your homework (due Monday) is 7.3 Section Assessment #1-2 on page 241.

1. What is an acid?
2. What are some common acids?
3. Acids taste a certain way… how do they taste and should you use that property to identify acids?
4. What does it mean to say that an acid is corrosive?
5. Which gas forms when an acid reacts with zinc, magnesium or iron?
6. What are the properties of a base?
7. What are three common bases?
8. Please give one safe way to identify a base.
9. What vitamin is an acid?
10. Which acid is used to clean bricks and metals?
11. Why is baking soda used in baking?
12. Drain cleaners are very potent materials. What substance do they contain and is it an acid or base?
13. Which substance is used to make fertilizers?
14. Where is folic acid found?

Also, check your grades over on http://www.mygradebook.com!

7.2: Concentration and Solubility

Here is the note sheet we completed in class today on section 7.2 (click).

Remember, your homework is Section 7.2 Section Assessment p. 235 #1-3!

1. What is a dilute solution? Please give an example.
2. How does a concentrated solution differ from a dilute solution?
3. How can you change the concentration of a solution?
4. When you make juice from concentrate by adding water, are you making a dilute or concentrated solution?
5. How do you measure the concentration of a solution?
6. Why can you only add so much sugar to sweet tea?
7. What is a saturated solution?
8. What does the solubility of a substance tell you?
9. What factors affect the solubility of a substance?
10. How does pressure affect the solubility of gases?
11. How do solvents affect how well a solute dissolves in liquids?
12. How are the solubility of solids affected by temperature?
13. What is a supersaturated solution?
14. Is NaCl or baking soda more soluble in water?
15. As temperature increases, what happens to the solubility of a gas?

See you tomorrow!

Class Notes for Wednesday October 21, 2009

Here are the notes we covered in class for section 7.1 on Solutions, Colloids and Suspensions.

Remember, your homework is the Section Assessment #1-3 on page 227!

1. What is a solution?
2. What is the difference between a solute and a solution?
3. What is the “universal solvent”? Give examples of these types of solutions.
4. What are some examples of solutions without water?
5. What is a colloid? Give an example.
6. Does a colloid or solution contain larger particles?
7. What is a suspension? Please give an example.
8. What is the difference between a solution and a suspension?
9. Why do solutes seem to disappear when you mix them with a solvent?
10. What happens when an ionic solid mixes with water?
11. What happens when a covalent (molecular) solid mixes with water?
12. How can you tell the difference between solutions of ionic compounds and solutions of covalent (molecular) compounds differ in water?
13. What do solutes do to the freezing point and boiling points of solvents? Please give an example.
14. How does salt lower the freezing point of water?
15. How does antifreeze use the properties of solutes and solutions to protect car engines?

See you tomorrow!