1. Chem 108 Expt #10: Analysis of KClO 3 How to weigh out the unknown and MnO 2

2. The objective of the experiment is to determine the % KClO 3 in an unknown mixture containing KClO 3 and KCl. The following slides are to help you understand the first few steps when you weigh out the catalyst, MnO 2 and the unknown. You do not need to record the mass of MnO 2 but you do need to make sure you have the right amount in the t-tube. You do need the mass of the unknown.

3. 0.000 g Tare to zero. 3a MnO 2 Remove t-tube and add a minute amt of MnO 2. 3b 0.100 g Return t-tube to balance and check mass. Do NOT tare again. 3c Repeat Steps 3b & 3c until balance reads between 0.1 and 0.15 g. Do NOT tare again. Do not record yet.

4. 0.000 g Remove t-tube and beaker, and zero the balance. 4 25.300 g Record (2 nd line) mass of beaker+ t-tube+MnO 2. Do NOT tare! 5 24.311 g Transfer all of unknown into t-tube 6 Record (1 st line) mass of beaker + t-tube + MnO 2 + unk.. 7 26.352 g Calc in notebook 26.352 g (Line 1) -25.300 g (Line 2) 1.052 g unknown