Pacific American School
High School Chemistry
Now What Do I Do
Kyle Teng
Grade 10
October 12th, 2012
Laboratory Background
Member List:
l Lab Instructor: June Zhang
l Lab Leader: Kyle Teng
l Lab Members: Kyle Teng, Jackie Jao, Jack Hsiao, Alex Chen
Introduction: The purpose of this lab is to let student experience and understand the actual lab
analytical Chemist participate. In this lab we will solve problems by making accurate
measurements and applying mathematics.
Materials: l Plastic Cup
l Balance
l Calculator
l Water
l Pen & Pencil
l Paper
l Penny before 1982
l Penny after 1982
l Small-scale pipet
l Aluminum can
Methods: Step 1: Measure the mass of the plastic cup by balance.
Step 2: Add 50 drops of water form the small-scale pipet in 50-degree angle to one
of the plastic cup and then measure it mass by balance.
Step 3: Add 50 drops of water from the small-scale pipet in 45-degree angle to one
of the plastic sup and then measure it mass by balance.
Step 4: Add 50 drops of water from the small-scale pipet in 0-degree angle to one
of the plastic sup and then measure it mass by balance.
Step 5: Use information that we found form the lab and experiment above to
calculate and came out an answer for the best degree for doping water.
Step 6: Use a balance to Measure the mass of the penny before 1982
Step 7: Use a balance to Measure the mass of the penny after 1982
Step 8: Use information that we found form the lab and experiment above to
calculate and came out an answer of which one lighter between penny before
1982 and penny before 1982.
Step 9: Use a balance to measure the mass of the aluminum can
Step 10: Used density formula to find the volume of the aluminum can
Data: Which is the Best Degree for Dropping Water?
Trial 1:
Degree angles while
dropping
Mass of Plastic Cup (g) After 50 drops of water/
the Mass of the Cup (g)
90 14.66 16.64
45 14.62 16.38
0 14.62 16.84
Trial 2:
Degree angles while
dropping
Mass of Plastic Cup (g) After 50 drops of water/
the Mass of the Cup (g)
90 14.66 16.82
45 14.66 16.68
0 14.66 16.86
Trial 3:
Degree angles while
dropping
Mass of Plastic Cup (g) After 50 drops of water/
the Mass of the Cup (g)
90 14.66 16.54
45 14.68 16.80
0 14.64 16.98
Mass of Coins
Coins before 1982 Coins after 1982
3.12g 2.58g
Aluminum Can
Mass of the aluminum can 5.6g
Density of aluminum can 2.70g/cm3
Results: In the experience “what is the best degree for dropping water?” trial 1, trial 2,
and trial 3 data shows the degree angle while dropping at the fist range, the mass of
plastic at second, and the mass of the plastic cup after 50 drops of water has been
dropped at third.
In the experience “mass of coin” the data shows the mass of coins before 1982 at
the first range and the mass of the coin after 1982 at the second. Coins after 1982 are
lighter Coin before 1982.
In the experience “aluminum can” the data show the mass of the aluminum can
which will later come out with volume, form the density formula.
Discussion and Analysis: In the experience “What is the Best Degree for Dropping Water?” we need to get
the mass of water to find the amount. The greater mass the more amounts, the more
amount the better.
To find the mass we need to subtract the mass of the plastic cup after 50 drops of
water to the mass of the empty plastic cup and then average it.
Trail 1:
90 degree, 16.64g – 14.66g = 1.98g
45 degree, 16.38g – 14.62g = 1.79g
0 degree, 16.84g – 14.62g = 2.22g
Trail 2:
90 degree, 16.82g – 14.66g = 2.16g
45 degree, 16.68g – 14.66g = 2.02g
0 degree, 16.86g – 14.66g = 2.20g
Trail 3:
90 degree, 16.54g – 14.66g = 1.86g
45 degree, 16.80g – 14.68g = 2.12g
0 degree, 16.98g – 14.64g = 2.34g
Average mass of 50 drops:
90 degree, (1.98g + 2.16g + 1.86g) / 3 = 2.00g
45 degree, (1.79g + 2.02g + 2.12g) / 3 = 1.98g
0 degree, (2.22g + 2.20g + 2.34g) / 3 = 2.25g
Average mass of 1 drop (1g = 1000mg):
90 degree, 2.00g / 50 = 0.04 = 40mg
45 degree, 1.98g / 50 = 0.0396 = 39.6mg
0 degree, 2.25g / 50 = 0.045 = 45mg
Average mass of all in one drop:
(40mg + 39.6mg + 45mg) / 3 = 41.5mg
Average volume of all in one drop (1000ul = 1ml):
Density = Mass / Volume
Density of water = 1.00g/ cm3 = 1000mg/ cm3 = 1000mg/ ml
1000mg/ cm3 = 41.5mg / Volume
Volume = 0.041.5cm3 = 0.041.5ml = 41.5ul
As a result the experience show us that dropping water form 0 degree is the best,
then 90 degree and 45 degree is the worst. To proof the result, we can see the number
after the calculation shows dropping from 90 degree angle in Trial 1 is more then the
dropping from 45 degree angle, but less then 0 degree angle, in Trial 2 is more then
dropping from 45 degree angle, but less then 0 degree, in Trial 3 is more then
dropping from 45 degree angle, but less then 0 degree.
(The result of this experiment seems little weird, because 90 degree angle should be
the one that drop the most, then 45 degree angle, and 0 degree angle the least. Not 0
degree the most, then 90 degree, and 45 degree the least. One of the reasons that cause
this problem is the inconstant amount of water per drop, which night lowers the
accuracy of the experiment.)
In the experience “mass of coins” we need to determine which coin are lighter,
Coin before 1982 or Coin after 1982. The reason why these two coins have different
mass is because these two coins contains different amount of copper and zinc.
• Pennies made before 1982 contains 95.0% copper and 5.0% zinc.
Mass of Copper: 3.12g × 95.0% = 2.964
Mass of Zinc: 3.12g × 5.0% = 0.156
• Pennies made after 1982 contains 2.4% copper and 97.6% zinc.
Mass of Copper: 2.58g × 2.4% = 0.06g
Mass of Zinc: 2.58g × 97.6% = 2.52g
In the experience “aluminum can” we need to find its volume form the density
formula with its mass.
• Density formula: Density = Mass / Volume
27.0g/ cm3 = 5.6g / Volume
Volume of the aluminum can = 0.207g/ cm3
Conclusions: The Purpose of these experiments above is tried to act like an analytical chemist.
We provide accurate measurement and mathematic calculations. Although, there are
some result seems weird in the experiment, most of then are successful and well done.
0.00% 20.00% 40.00% 60.00% 80.00% 100.00% 120.00%
Coin After 1982
Coin Before 1982
Material for Coins Before and After 1982
Copper Zinc
Figures and Graphs:
References: Wilbraham, Staley, Matta, Waterman. Prentice Hall Chemistry. Pearson plc:
London, n.d. Print.
Trail 1 (g) Trail 2 (g) Trail 3 (g) Average (g) 90 Degree 1.98 2.16 1.86 2 45 Degree 1.79 2.02 2.12 1.98 0 Degree 2.22 2.2 2.34 2.25
1.98 2.16
1.86 2
1.79 2.02 2.12 1.98
2.22 2.2 2.34 2.25
Water Drops by Angle
90 Degree 45 Degree 0 Degree
