Name of Experiment: Law of Definite Proportions
Please show each step each/all step/s in the solving of each problem in this assignment; Please show your work for each question, problem and or response, by use of data tables, graphs, set-ups with units throughout your work, road maps with units, balanced equations, chemical symbols, correct number of significant figures in final answers, etc.
The lab work sheet consists of Experiment 1 and Part 2.
Experiment 1:
1. Calculate and record the following for the experiment performed with 20g KClO3:
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a
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mass of the crucible with manganese(IV) dioxide (in grams)
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b
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mass of the crucible after potassium chlorate has been added (in grams)
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c
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mass of the crucible after heating (in grams)
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d
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mass of oxygen in sample of potassium chlorate (in grams) [(b) minus (c)]
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e
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mass of potassium chloride (in grams) [the mass of the original potassium chlorate added to the crucible minus (d)]
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2. Calculate your experimental mass percent of oxygen in KClO3 according to:
Experimental mass percent of oxygen = [mass of oxygen lost (d)] / (mass of KClO3 added to the crucible)
3. Using a Periodic Table (you can access one from this link http://en.wikipedia.org/wiki/File:Periodic_table.svg , if one is not readily available to you) Find the elements K, Cl and O, and click on each one to find their atomic weights. Use these to calculate a theoretical mass percent of oxygen in KClO3 according to:
theoretical mass percent of oxygen = (mass of 3 oxygen atoms) / (molecular weight of KClO3)
4. Calculate the percent error in the experiment using the experimental and theoretical values of the mass percent of oxygen. The percent error is defined as:
|(experimental value) - (theoretical value)| / theoretical value * 100%
5. How well does your experimental result match the theoretical value? What sources of error may explain the discrepancy?
Part 2: The Law of Definite Composition Questions: Please answer the following questions with the correct answer
A student performs a thermal decomposition experiment using 35.00 g of lithium iodate, LiIO3. The weight of the crucible decreases by 8.95 g after heating. The theoretical mass of oxygen in LiIO3 is 9.24 g. What is the percent error in the student's experiment?
2. A student calculates a 75% percent error. What can be said about the experimental value obtained in the experiment?
3. A student calculates a 0.54% percent error. What can be said about the experimental value obtained in the experiment?