Exam
Study guide
Reaction in the bag lab
Materials:
- substance A & B
- 2 spoons
- graduated cylinder
- red liquid
- zip lock bag
- water
- wear goggles
- wear apron
Substance B is Baking Soda
Heating baking soda
Materials
- baking soda
- tea
- two test tubes
- water
- bottle
- rubber band
- container
- stirring rod
- peg board
- rubber tube
- glass bend
- stopper
- burner
- matches
- clamp
experimental: heated test tube
indicator: tea (showed that heated it is no longer baking soda)
variable: a category you try to measure
independent variable: causes a change in the dependent variable (temperature)
Dependent variable: color of tea
control factors : Things we can control
- using same type of tea
- same amount of baking soda and tea
- same size test tube
- same stirring time
- hole in tubbing
- stopper not snug
Is the amount of condensation that forms at the top of the heated test tube more or less than the amount of baking soda being heated?
Less or equal to because condensation comes from baking soda it cannot prodyce more than itself
Lab safety notes
- goggles must be kept over your eyes until Mr. Leeds says to put them away
- report ALL accidents/spills to Mr.Less immediately
- try you best to use common sense
Safety Equipment
- fire extinguisher
- fire blanket
- Eye wash/ shower
Chemicals
- never taste chemicals
- always WAFT liquids to detect odor
- Never WAFT solids/ powders
- avoid touching chemicals
- ALways wash hands with soap and water after lab
- if chemicals touch skin: flush skin with water for 1 minute AND notify Mr.Leeds
- Hot glass look the same
- never use chipped or broken glass: tell Mr.Leeds and dispose of broken glass in proper trash
- never force to remove or insert glass
Alcohol Burners
- roll up sleeves put UP long hair NOT just pull back
- never walk away from a lit burner
- never point the open end of a hot test tube at yourself or someone else
- Do not look down into a test tube/beaker while it is being heated
- Make sure burner is capped and flame is out when done
- Clean up Area & Materials completely
- make certain that burner is out if one was used
- keep goggles on (over eyes) until Mr.Leeds says to put them away
Ice Ice Baby lab
I. Purpose: To determine if the mass of ice will increase, decrease, or stay the same when it melts
II. Procedure:
1. Zero the balance and clean the pan
2. Dry cap and bottle
3. Mass the bottle/cap
4. Mass the bottle/cap with ice
5. Melt the ice
6. Mass the bottle/cap with water
III. Materials:
1. Water
2. Cap
3. Ice
4. Balance data
IV. Lab Safety: N/A
V. Data and/or Observations:
Mass of bottle/ cap (g)
5.460
5.451
Mass of bottle/cap with ice (g)
7.430
6.468
MI of Ice (g)
1.970
1.017
Mass of bottle/cap with water (g)
7.430
6.468
MF of water (g)
1.970
1.017
Delta M
0
0
VI. Experimental Errors:
1. The ice hasn’t fully melted and you weigh it
2. If there is a crack in your bottle
The Mass of Dissolved Salt Lab
I. Purpose:
To determine if the mass of salt decreases when salt dissolves in H2O
II. Procedure:
1. Check pan/ Zero balance
2. DRY CAP and then mass cap
3. Add 2g to the balance
4. Add salt to cap until balanced
5. Fill bottle 2/3 with H2O
6. Mass bottle with H2O and cap with salt together but NOT MIXED
7. Pir salt into bottle
8. Shake bottle until salt dissolves
9. Mass bottle with CAP ON
10. Calculate Change in mass: final mass- initial mass
III. Materials:
· Salt
· Bottle
· Cap
· Water
· Balance
· Scooper
IV. Lab Safety: N/A
V. Data and/or Observations:
Initial Mass
Final Mass
Change in mass
1
17.388
17.353
0.035
2
18.302
18.138
-0.164
VI. Experimental Errors:
· Clean pan between initial mass and final mass
· Outside of bottle is wet during initial mass
The Density of a Solid Lab
I. Purpose: To use density to determine if 3 metal objects are made of the same substance.
II. Procedure:
1. Zero balance the scale
2. Mass the cubes separately
3. Answer blue dot question number 1
4. Mass the slab
5. Answer blue dot question number 2
6. Measure the dimensions of each of the three objects
7. fund the volume and mass of an irregular shaped object (rock)
8. calculate density of rock
III. Materials:
1. Rock
2. Ruler
3. Balance
4. 3 metal objects
5. Graduated cylinder
6. Water
7. Lighter
IV. Lab Safety: N/A
V. Data and/or Observations:
Object
Length (cm)
Width (cm)
Height (cm)
Cube 1
1.20
1.20
1.20
Cube 2
1.20
1.20
1.20
Slab
7.60
2.50
.60
Object
Volume (cm3)
Mass (g)
Density (g/cm3)
Cube 1
1.728
5.651
3.27
Cube 2
1.728
15.750
9.12
Slab
11.40
33.701
2.95
Rock
1.6
4.207
2.62
1. Cube 2
2. It’s different
VI. Experimental Errors:
1. If you find the volume of the rock before the mass
2. If you but the rock in and water splashes out
Sensitivity of a Balance Lab
I. Purpose: To observe if you mass the same object repeatedly will the mass remain the same also to find out how different the masses of two objects must be for our balance to detect the difference
II. Procedure:
Part A
1. Clean pan/ Zero balance
2. Mass penny stopper alternately 4 times
3. Do not share data until finished ALL massing
Part B
1. Zero balance
2. Cut out a 20 x20 square
3. Mass the large square
4. Calculate mass of 1 small square (divided by 400)
5. Figure out how many squares are between .0033 .0075
6. Cut out 10 groups of squares (between .003-.007)
7. Mass stopper leave it in pan and don’t move riders
8. Add groups of squares one at a time and record mass and changes
III. Materials:
· Stopper
· Penny
· Balance
· Graph paper
· Scissors
IV. Lab Safety: N/A
V. Data and/or Observations:
Part A
#
Mass of penny (g)
Mass of stopper (g)
1
3.000
8.192
2
3.051
8.193
3
3.100
8.200
4
3.050
8.220
Part B
Square Calculations
Mass of 20x20
0.630
Mass of single square
0.001575
Mass of 4 square in group
0.0063
Initial mass of stopper 12 g
# of groups
Change in mass (yes or no)
Mass (g)
1
No
12
2
Yes
12.010
3
Yes
12.020
4
Yes
12.045
5
Yes
12.050
6
Yes
12.060
7
Yes
12.090
8
No
12.090
9
No
12.090
10
Yes
12.100
Sensitivity of Balance
Sensitivity number of yes’s
0.100
Number of yes’s
7
Sensitivity
0.0142857
Blue Dot Questions
1. Does your balance give the same results to the nearest 0.01 g? the nearest 0.001g? or something in between?
The same number to the hundredths place for the penny and the hundredths for the stopper
2. How many groups of squares did you have to add before the balance gave you an observable response?
There is no pattern because every time the balance went up a point or just stayed the same
VI. Experimental Errors:
1. The book company accidently made one of the squares bigger
2. If the calculator wasn’t working correctly
The Mass of Copper and Sulfur Lab
I. Purpose: To see if the total mass increases, decreases, or stays the same when sulfur and copper are heated together
II. Procedure:
1. Clean and zero balance your pan
2. Mass the test tube, sheet, & rubber band
3. Mass 2g copper
4. Mass the paper towel
5. Add a gram to the balance
6. Mass the sulfur
7. Find the Mi of copper and sulfur
8. Put the copper and sulfur in a test tube
9. Ask Mr. Leeds if you can light the burner
10. Light the burner
11. Heat the mixture gently until it begins to glow
12. Remove the flame immediately
13. Mass the test tube, sheet, band, copper, and sulfur heated
14. Find the Mf of copper and sulfur
15. Find the Delta M
16. Clean up
III. Materials:
· Sulfur
· Copper
· Balance
· Large test tube
· Peg board
· Large clump
· Rubber sheet
· Rubber band
· Burner
· Matches
· Paper towel
IV. Lab Safety: Wear goggles and apron and put your hair up.
V. Data and/or Observations:
Mass of test tube/ sheet/ band
33.691
Mass of test tube/ sheet/ band/copper/ sulfur unheated
36.648
MI of copper and sulfur
2.957
Mass of test tube/ sheet/ band/ copper/ sulfur heated
36.645
MF of copper and sulfur
2.954
Change in Mass
-.003
VI. Experimental Errors:
1. There can be holes in the sheet.
2. There can be sulfur in the pan during the measurement of the sulfur and not there during anything else.
The Density of a Liquid lab
I. Purpose: To use density to compare 2 liquids to determine if they are the same substance
II. Procedure:
1. Zero/check pan
2. Waft liquid
3. Mass empty cylinder
4. Fill graduated cylinder with 10cm3 of liquid
5. Mass graduated cylinder with liquid
6. Pour liquid into sink
7. Clean-up and repeat with other liquid
III. Materials:
1. Liquid A
2. Liquid B
3. Scale
4. Graduated Cylinder
5. 2 beakers
IV. Lab Safety: Safety goggles and apron
V. Data and/or Observations:
Liquid
Mass of Empty Cylinder
(g)
Mass of liquid and cylinder
(g)
Mass of liquid
(g)
Volume of liquid
(cm3)
Density of liquid
(g/cm3)
A
14.95
26.44
11.49
10
1.15
B
14.96
25.24
10.28
10
1.03
VI. Experimental Errors:
1. If someone before you put the substance back into the main jar. This would possibly put other substances in it.
2. You measure the graduated cylinder then clean out the water from it this would cause a lose in weight.
The Density of a Gas Lab
I. Purpose: To produce and collect a gas in order to accurately figure out the density of the gas
II. Procedure:
1. Clean pan/ Zero balance
2. Break the tablet
3. Fill test tube with about 5cm3 of water
4. Mass 2 halves tablets and test tubes with water and rubber band
5. Find volume of bottle (fill bottle and empty it into the graduated cylinder)
6. Set up the apparatus (no air bubbles)
7. Have Mr. Leeds check set up
8. Put tablet in test tube
9. Insert stopper
10. But the tube in the bottle
11. Remove tube from bottle when reaction ends
12. Remove stopper
13. Carefully invert bottle out of container
14. Find volume of H2O left in bottle
15. Mass test tube with H2O, foil, and rubber band
16. Clean up
17. Calculate density of the gas
III. Materials:
1. Balance
2. Water
3. Foil
4. Alka-Seltzer
5. Test tube
6. Stopper
7. Glass bend
8. Rubber tubing
9. 2 rubber band
10. Containers
11. Peg board
12. Bottle
13. Clump
14. Graduated cylinder
IV. Lab Safety: Goggles
V. Data and/or Observations:
Mi (g)
Mf (g)
Delta M (g)
Vi (cm3)
Vf (cm3)
Delta M (cm3)
Density (g/ cm3)
40.251
39.365
-0.886
539.2
247.8
-291.4
3.0
VI. Experimental Errors:
1. Put foil back for MF
2. Touching tablets after MI