Don’t forget: Change your clocks AHEAD 1 hr on Saturday night!

Friday, March 7 th : “A” Day Monday, March 10 th : “B” Day Agenda  Check lab write-ups  Lab discussion  Lab: “Making a Solubility Curve for KNO 3 ” Lab will be due next time…

“Making a Solubility Curve for KNO 3 ” Lab Hints 1.The granular KNO 3 will roll around on the balance if you use weighing paper – use a small weighing boat instead. 2.Use DISTILLED WATER instead of water out of the tap to prepare your test tubes. 3.Make sure your measurements are ACCURATE – 2.0 g KNO 3 and 5.0 mL of water, etc. Use squirt bottles to get exactly 5.0 mL of water if needed.

“Making a Solubility Curve for KNO 3 ” Lab Hints 4. When dissolving the KNO 3 in the hot water bath, BE CAREFUL putting in the rubber stopper and shaking the test tube – the test tube will be HOT! 5. DO NOT shake the test tube too vigorously – the solid KNO 3 will stick to the sides of the test tube above the water level.

“Making a Solubility Curve for KNO 3 ” Lab Hints 4.When the KNO 3 has dissolved, set the test tube in the rack to cool – do not disturb the test tube as it cools. 5.When you first see signs of crystals forming, put in the temperature probe and record the temperature. You will need to WATCH CLOSELY! 6.Be sure to WIPE OFF the temperature probe each time.

“Making a Solubility Curve for KNO 3 ” Calculations  Units for solubility curves are generally grams solute 100 mL H 2 O you will need to use PROPORTIONS to convert your data: 2.0 g KNO 3 = X g KNO mL of H 2 O 100 mL H 2 O  Solve for X

“Making a Solubility Curve for KNO 3 ”  Don’t forget to complete your REFLECTION STATEMENT!  Don’t forget to update your TABLE OF CONTENTS!  Please use the squirt bottle of soap to clean off your lab table when you finish.  Be safe and have fun! Lab will be due next time…