2.5-2.6
(Part dos of the chapter dos test)
2.5 The Mass of Copper and Sulfur
Purpose: To determine if the total mass of sulfur and copper increases, decreases, or stays the same when they are heated together.
Procedure:
- Clean pan and zero balance
- Find mass of test tube, sheet, and band together
- Add 2 grams to balance
- Measure 2 grams of copper until balanced
- Add copper to test tube
- Mass piece of paper towel
- Add 1 gram to balance
- Add sulfur to paper towel until balanced
- Add sulfur to test tube
- Cover top with rubber sheet and wrap rubber band around tube to secure
- Record mass of test tube, sheet, band, sulfur, and copper unheated
- Have Mr. Leeds check setup
- Light burner, heat mixture, and observe
- When reaction ends, cap flame
- Find mass of heated test tube, sheet, band, sulfur, and copper
- Clean up
- Balance
- Paper towel
- Large test tube
- Rubber sheet
- Rubber band
- Sulfur
- Copper
- Burner
- Matches
- Large clamp
- Pegboard
- Melting point of copper is 1100 C (2000 F)
- Melting point of sulfur is 112 C (235 F)
Yellow Smoke:
- Water in sulfur turns to vapor (gas) and rises in test tube
- When it cools, sulfur bonds with copper, forms copper sulphide
- Hole in rubber sheet, gas could escape, decrease in mass
- Sheet pops off, gas could escape, decrease in mass
- Rubber band pops off, gas could escape, decrease in mass
- Not sealed around top of test tube, gas could escape, decrease in mass
- Sulfur sticks to sides of test tube, doesn't react with heat
2.6 The Mass of a Gas Lab
Purpose: To determine if the mass will increase, decrease, or stay the same when a solid and liquid produce a gas.
Procedure:
- Clean and zero balance
- Fill bottle 1/3 with water
- Mass bottle, cap, and tablet in cap (dry cap)
- Put tablet in bottle (don't touch with hands)
- Wait 30 seconds and mass bottle
- Slowly loosen cap (DON'T REMOVE)
- Mass bottle
Materials:
- Alka-Seltzer tablet
- Bottle
- Water
- Balance
- Cap
Lab Safety: -Wear goggles
Experimental Errors:
- Water in pan during Mi, lose mass
- Cap is wet during Mi, lose mass
- Touch tablet after Mi, lose mass
- Cap is not tight or on quickly enough, lose mass
- Antacid (suppresses acid) and pain reliever
- 3 ingredients: aspirin, citric acid, and sodium bicarbonate (which produces a gas)
2.7 The Conservation of Mass
Closed System: A space where nothing can enter or leave
Groups that had no change in mass (including sensitivity of the balance):
- 2.1: 75%
- 2.4: 75%
- 2.5: 50%
- 2.6: 48%