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Chem 1A - Exp1 Part A - Pre-Lab Exercises

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Chemistry 1A
Name _____________________________
Experiment 1: Part A - Pre-Lab Exercises
Investigating the Precision and Accuracy of Assorted Glassware
Answer the following questions in the space provided below each question. Show mathematical set-up
and work wherever applicable. For numerical answers, write the final answer in the box provided.
1.
On volumetric glassware you will see the markings T​D​ or T​C​. Explain what these symbols mean
in your own words. Cite your sources for any information that you look up on internet.
2.
An empty 100mL beaker weighs 78.0230 g. A student uses a pipet to transfer distilled water (at
21.4​o​C) into the beaker. The beaker plus the water weighs 97.4668 g. Based on the mass of
water, what ​volume​ of water did the student transfer? Use the density table and pay attention to
your significant figures!
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Chemistry 1A
3.
Name _____________________________
A student does an experiment to determine the specific heat of iron metal. The student repeats
the experiment 5 times and gets the following values for specific heat (all in J/g o​​ C): 0.463,
0.449, 0.451, 0.427, and 0.480. The accepted value for the specific heat of iron is 0.450 J/g o​​ C.
a) Calculate the student’s percent error and write it in the box below. Does the percent error
evaluate the ​accuracy​ or the ​precision​ of the student’s measurements? Explain.
b) Calculate the standard deviation for the student’s data set and write it in the box below.
Does the standard deviation evaluate the ​accuracy​ or the ​precision​ of the student’s
measurements? Explain.
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Chemistry 1A
Name _____________________________
4.
A 1-carat diamond has a mass of 200.0 mg. When a jeweler repeatedly weighed a 2-carat
diamond, he obtained measurements of 450.0 mg, 453.0 mg, and 455.0 mg.
a) Were the jeweler’s measurements accurate?
b) Were they precise?
Explain showing the necessary calculations.
5.
Report the volume of liquid in the graduated cylinders given below to the correct number of
significant figures​.
_______________ mL
6.
______________ mL
A students fills a 50 mL buret with salt solution to the zero mark and dispenses some of
the solution into an erlenmeyer flask. The image of the buret after dispensing the solution
is given on the right. Report the volume of salt solution dispensed to the correct number
of ​significant figures​.
___________ mL
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