DATA AND CALCULATIONS Sample Mass of sample Mass of filter paper, funnel top, copper, and beaker 118.96 Mass of filter paper, funnel top, and beaker Mass of copper Percentage of copper in sample Molar mass of sample Average molar mass of sample Calculations: Show all work Cu in sample I: 0.536 (0.08) Cu in sample II: 43.60
The Correct Answer and Explanation is:
Based on the provided data and calculations, here are the correct completed answers for the worksheet.
Completed Data Table:
- 5. Percent of copper in sample: 26.195 %
- 6. Molar mass of sample: 242.60 g/mol
- 7. Average molar mass of sample: 242.60 g/mol
Explanation
The student’s work on the worksheet is arithmetically correct, and the answers are derived directly from their calculations. The goal of this experiment was to determine the composition and molar mass of an unknown copper compound.
First, the percent of copper in the sample is calculated. This is a standard percent composition calculation, which uses the formula: (mass of the part / mass of the whole) × 100. In this case, the mass of the isolated copper (the part) was found to be 0.526 grams. This was divided by the total mass of the initial sample (the whole), which was 2.008 grams. Multiplying the result by 100 gives the percentage. The calculation, (0.526 g / 2.008 g) × 100, correctly yields 26.195%. This value fills line 5 and represents the mass percentage of copper in the unknown compound.
Next, this percentage is used to determine the formula mass, or molar mass, of the entire sample. This calculation is based on the idea that the ratio of an element’s mass in a compound is proportional to its molar mass contribution. The formula used is (Molar Mass of the Element / Percent Composition of the Element) × 100. Using the known molar mass of copper (63.55 g/mol ) and the experimentally determined percent composition (26.195%), the calculation (63.55 g/mol / 26.195) × 100 results in 242.60 g/mol . This is the experimental molar mass of the entire unknown compound.
Finally, the “Average molar mass of sample” is requested. Since the data for “Sample 2” was crossed out and only one trial was completed, the average is simply the result from the single trial, which is 242.60 g/mol .thumb_upthumb_down
