Unknown summary sheets can be picked up from the shelves next to the stockroom (room 4.134), or printed off from the PDF files below. Turn in the unknown summary sheet with your lab write-up.
Make sure you include your **unknown number**, your **unique number**, and your **TA's name** on your unknown summary sheets.
Experiment 2 Your unknown number is A, B, or C. Your TA will assign you one of these.
Experiment 3 Your unknown number is your lab drawer number.
Experiment 4 Your unknown number is your lab drawer number.
Experiment 7 Your unknown number is your lab drawer number.
Experiment 8 Your unknown number is your lab drawer number.
How are unknown summary sheets graded?
Each unknown summary sheet is worth 20 points, and is graded strictly on accuracy.
**Experiment 2:** your results for SiO2 and NaCl are worth up to 7 points each, and your results for CaCO3 are worth up to 6 points. There is an initial window of +/- 3% for full credit, and then the window widens by one percentage point in each direction, so there is a sliding scale where you get more points for greater accuracy, and fewer points for less accurate results.
For example, if your unknown had NaCl at 30%, any result between 27-33% would be worth full credit (7 points). Then 26%-34% would be 6 points, 25%-35% would be 5 points, and so on.
**Experiment 3:** 4 points for each unknown correctly identified.
**Experiment 4:** 5 points for correctly identifying your unknown acid (all or nothing), and 15 points for the accuracy of your acid concentration results (sliding scale).
**Experiment 7:** 10 points for your reported value for moles/gram of oxalate, and 10 points for your reported value for moles/gram of iron. Both of these are graded on a sliding scale.
**Experiment 8:** 10 points for correctly identifying your unknown metal (all or nothing) and 10 points for the specific heat capacity of your metal (sliding scale).
If you report a bad value because of a calculational error, you can fix the calculation and turn it in for a regrade. You will need to turn in the original unknown summary sheet, a page showing the corrected calculation, and a new unknown summary sheet marked REGRADE at the top. You can resubmit an unknown summary sheet only for a calculational error correction. No other regrades (for example, using class data instead of your own data for Experiment 2 or Q-testing a value and resubmitting) will be accepted.
What is an unknown summary sheet? Check the FAQ, Jack! |