CHEM 133 Week 10 Lab 10 Assignment

Question 1 of 12

Please upload (in PDF format) a picture of your metal sample being massed (Step 2d). To receive credit, your metal and the mass readout must be clearly visible in the picture, as well as a clear label with your name, the lab title (with Experiment number), and the date in clear view. This must be a single picture in a PDF file in order to receive credit.

NOTE: If your document is not clear, organized, and properly labeled, or any part of it is unclear to your instructor, you will not receive credit.

Question 2 of 12

8.0/ 8.0 Points

Please upload (in PDF format) a picture of you heating your metal strips (Step 2e). To receive credit, you must be clearly visible holding the metal strips in the picture, and it must include a clear label with your name, the lab title (with Experiment number), and the date in clear view. This must be a single picture in a PDF file in order to receive credit.

NOTE: If your document is not clear, organized, and properly labeled, or any part of it is unclear to your instructor, you will not receive credit.

Question 3 of 12

Please upload (in PDF format) a picture of your assembled calorimeter with final temperature reading (Step 2h). To receive credit, your full calorimeter and temperature reading must be clearly visible in the picture, as well as a clear label with your name, the lab title (with Experiment number), and the date in clear view. This must be a single picture in a PDF file in order to receive credit.

NOTE: If your document is not clear, organized, and properly labeled, or any part of it is unclear to your instructor, you will not receive credit.

Question 4 of 12

Please upload (in PDF format) a picture of your Table 2: Specific Heat Data from Experiment 1: Determination of Specific Heat of a Metal (Step 4). This must be a single PDF file in order to receive credit.

NOTE: If your table is not clear, organized, and properly labeled (with units), or any part of it is unclear to your instructor, you will not receive credit.

Question 5 of 12

Please upload (in PDF format) a picture of your spoonful of ammonium nitrate being transferred to your calorimeter (Step 5). To receive credit, your calorimeter and the ammonium nitrate must be clearly visible in the picture, as well as a clear label with your name, the lab title (with Experiment number), and the date in clear view. This must be a single picture in a PDF file in order to receive credit.

NOTE: If your document is not clear, organized, and properly labeled, or any part of it is unclear to your instructor, you will not receive credit.

Question 6 of 12

Please upload (in PDF format) a picture of your Table 4: Cold Pack Data and Table 5: Hand Warmer Data from Experiment 2: Cold Packs vs. Hand Warmers (Step 6). This must be a single PDF file in order to receive credit.

NOTE: If your table is not clear, organized, and properly labeled (with units), or any part of it is unclear to your instructor, you will not receive credit.

Question 7 of 12

In Experiment 2: Cold Packs vs. Hand Warmers, according to your experimental results:

1) Calculate the overall temperature change for the cold pack, ΔT = T_max - T_min

2) Explain why this reaction is considered endothermic.

Show all work and be detailed in your response in order to receive credit.

The cold pack is endothermic as energy is being brought into it from the outside environment which causes the surroundings to cool down.

Question 8 of 12

a picture of your Table 5: Enthalpy Data from Experiment 3: Measuring the Enthalpy of Fusion of Water (Step 8). This must be a single PDF file in order to receive credit.

NOTE: If your table is not clear, organized, and properly labeled (with units), or any part of it is unclear to your instructor, you will not receive credit.

Question 9 of 12

8.0/ 8.0 Points

Calculate the heat lost by the hot water using your results for Experiment 3: Measuring the Enthalpy of Fusion of Water. Heat must be expressed in kilojoules (kJ).

Q= (4.18 J/g °C) x (1 kJ/1000 J) x mass of water (g) x ΔT

NOTE: All work must be shown. Skipping steps or lack of clarity in steps will result in loss of points. All units must be properly labeled. Be sure to click on "Show/Hide Rich Text Editor" above your answer box so you can include subscripts, superscripts, etc. as needed. If your formatting is unclear, you will not receive credit.

Question 10 of 12

Using your results for Experiment 3: Measuring the Enthalpy of Fusion of Water, calculate the molar heat of fusion of ice, i.e., the number of kilojoules of heat per mole ice.

q = ΔH_fusm

NOTE: All work must be shown. Skipping steps or lack of clarity in steps will result in loss of points. All units must be properly labeled. Be sure to click on "Show/Hide Rich Text Editor" above your answer box so you can include subscripts, superscripts, etc. as needed. If your formatting is unclear, you will not receive credit.

Question 11 of 12

Using your results for Experiment 3: Measuring the Enthalpy of Fusion of Water, calculate the percent error in your determination of the value for the molar heat of fusion of ice.

Percent Error = |Experimental - Actual|/ (Actual) x 100 = % Error

NOTE: All work must be shown. Skipping steps or lack of clarity in steps will result in loss of points. All units must be properly labeled. Be sure to click on "Show/Hide Rich Text Editor" above your answer box so you can include subscripts, superscripts, etc. as needed. If your formatting is unclear, you will not receive credit.

47.5%

Question 12 of 12

4.0/ 4.0 Points

Answer the following Post-Lab Questions on potential sources of error in this experiment.

1) What could have or did go wrong?

2) How might this have impacted your data?

3) How could you address/fix such errors in future experiments?

Many differences come into play with chemistry therefore, even the slightest weight variation or calibration error could render the final experiment with unsuitable results.
By maintaining an accurate detailed list of all data used or gathered in this experiment, we can come to the conclusion that there will always be a slight deviation from the predicted results and we can further alter them to remove any additional errors with any other experiments we use.