# Science2 Essay

This essay has a total of 1502 words and 8 pages.

science2

Objective: To practice the various techniques of measuring masses using the lab balance.
Then to gain the experience in the techniques of handling lab equipment.

Procedure:
1. Check your balance to make sure that the pointer is calibrated or zeroed. If
necessary, consult your teacher for an adjustment.

2. Place a penny on the balance pan. Move the riders until the pointer is balanced. Record the mass of the penny.
3. Repeat step two for objects listed below.

A. Nickel
B. A watch glass
C. A 150-ml beaker
D. A 100-ml graduated cylinder

-Measure and record the mass of a watch glass.
-Obtain 20-25 salt crystals on a piece of paper. Transfer them to the watch glass carefully.
-Measure and record the combined mass of the watch glass and the calcium chloride. Make
sure you record the time it took you to make this measurement.

-Using your micro spatula, spread the crystals out on the watch glass and record you observations.
-Measure and record the mass of a piece of filter paper.
-Obtain some salt on a piece of paper. Using your micro spatula, place one scoop of the
sodium chloride on the piece of filter paper. Record the combined mass.

-Add another scoop of salt on to the filter paper and record the combined mass.
-Add a third scoop to the filter paper. Record that measurement then discard the paper and the salt.

1. Mass of a penny = 3.08 grams
2. Mass of a nickel = 5.03 grams
3. Mass of a watch glass = 55.82 grams
4. Mass of a 150 ml beaker = 58.43 grams
5. Mass of a 100 ml graduated cylinder = 65.25 grams
6. Mass of a watch glass = 55.83 grams
7. Mass of a Watch glass plus Calcium chloride = 59.51 grams
8. Time of measurement = 11:35
9. Mass of filter paper = 48 grams
10. Mass of filter paper plus one scoop of NaCl = 2.88 grams
11. Mass of filter paper plus two scoops = 4.09 grams
12. Mass of filter paper plus three scoops = 7.34 grams
13. Mass of 150 ml beaker = 66.80 grams
14. Mass of 150 ml beaker plus 30 ml water = 95.21 grams
15. Mass of inflated balloon = 1.54 grams
16. Mass of deflated balloon = 1.46 grams
17. Time of measurement = 11:40

Calculations
A. CaCl2 crystals added to the watch glass = 3.6 grams
B. NaCl one scoop (step 14-15) = 2.41 grams
C. NaCl two scoops (16-14) = 3.62 grams
D. NaCl three scoops (16-14) = 6.87 grams
E. 30 ml of water (19-18) = 28.48 grams
F. Moisture Absorbed by CaCl2 crystals (22-12) = 0.01 grams

4. Calculate the difference in mass between the inflated and the deflated balloon = 0.08 grams
5. Calculate how much time elapsed between the 2 measurements of the CaCl2 = 5

Conclusion and questions:
A. From calculation 3, what was the mass of the first scoop of NaCl? = 2.88 grams
B. From your data, calculate the masses of the second scoop and the third scoop of NaCl = 3.26 grams.
C. Compare the masses of each individual scoop of NaCl as determined in A & B above. Are
the three values identical? If not, how do you account for the differences? = No they are
different because the weight of each of the scoops changed the look and the moisture

D. What measurements would you make to determine the average mass of a heaping micro
spatula of NaCl? How would you see these measurements to arrive at an average mass? = You
can add up each of the scoops and then divide them by the number of scoops.

E. The difference between the mass of the balloon when inflated and its mass after
punctured is not an accurate determination of the mass of the gas in the inflated balloon.
Why is this? = The balloon still has air in it after it is punctured.

Conclusion: In this lab I learned how to find the masses of objects by using the balance.
I also learned that there are a couple ways of measuring mass. You can use a balance. You
could also calculate the difference in the two masses to find the mass. This lab came
very easy to me because I paid attention in class, and I also remembered this from 8th
grade. This lab refreshed my memory a bit.

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