Standard Operating Procedure SOP Double panDouble beam Balance

Standard Operating Procedure (SOP) – Double pan/Double beam Balance Calibration Verification 1. Be sure the balance is on a flat stationary surface 2. Ensure the 10 gram increment is set to 0 3. Ensure the 1 gram increment is set to 0 4. Check the balance point and observe it damping location 4. 1 If the balance point is centered move on to Step 5 4. 2 If the balance point is not centered 4. 2. 1 Adjust the (counter weight) calibration mechanism 4. 2. 2 Allow the balance point to damp Repeat 4. 2. 1 and 4. 2. 2 until the balance points damps center 5. Check the calibration of the balance’s pans and beams 5. 1 Pan Calibration Check 5. 1. 1 Place a 50 gram weight on the left pan 5. 1. 2 Place the equivalent weight on the right pan 5. 1. 3 Verify the balance point is centered 5. 1. 3. a If balance point is centered remove all weights and proceed to Step 6 5. 1. 3. b If balance point is not centered, remove all weights and return to Step 4. 2 5. 2 “ 10” Gram Increment Beam Calibration Check 5. 2. 1 Place 30 grams on the left pan 5. 2. 2 Adjust the 10 gram beam weight to the equivalent (30 g) weight 5. 2. 2. a If balance point is centered, remove all weights, reset the beam to 0 and proceed to Step 5. 3 5. 2. 2. b If balance point is not centered, remove all weights and return to Step 4. 2 5. 3 “ 1” Gram Increment Beam Calibration Check 5. 2. 1 Place 3 grams on the left pan 5. 2. 2 Adjust the 1 gram beam weight to the equivalent (3 g) weight 5. 2. 2. a If balance point is centered, remove all weights, reset the beam to 0 and proceed to Step 6 5. 2. 2. b If balance point is not centered, remove all weights and return to Step 4. 2 6. Certify to the person in charge (teacher) the balance is ready for use

Standard Operating Procedure (SOP) – Burette Operation Burette Preparation 1. Rinsing the burette A. Be sure the stopcock on the burette is closed B. Fill the burette with a rinse solution of water C. Carefully mount the burette in the stand D. Place a collection vessel beneath the stopcock and adjust the burette’s height in the stand as required E. Drain the rinse solution i. Drain approximately half the contents into the collection vessel ii. Close the stopcock when empty 2. Conditioning the burette • Pour a small quantity of titrant into the burette A. Carefully roll the burette so that the titrant contacts all of the burette’s interior walls (you may cap or use paraffin over the end) B. Open the stopcock to drain the titrant into the collection vessel A. Final preparation for titrating A. Ensure the stopcock is closed B. Fill the burette with titrant A. i. Note: Going beyond the 0 mark at the top is permissible Carefully mount the burette in the stand ii. Examine the burette for bubbles in the column • 1. Gently tap the burette to cause any trapped air bubbles to rise 2. Be sure to examine the area within the collar of the burette • Drain titrant through the stopcock to remove any trapped air bubbles form this area • Via the stopcock, drain the titrant level to the nearest whole marking Certify to the person in charge (teacher) the burette is ready for use

Standard Operating Procedure (SOP) – Double pan/Double beam Balance Operation - Using a balance certified for use 1. Tare out a clean weighing boat using the left pan 2. Transfer some of the required chemical (table salt) to a second weighing boat 3. Using the appropriate tools and technique A. Weight out the required amount of chemical B. Dispose of the excess chemical appropriately Standard Operating Procedure (SOP) – Making a Standard Solution Volumetric Standard 1. Rinse and empty a select volumetric flask 2. Bring the volumetric flask up to most of its volume 3. Prepare to add the applicable amount of standard and bring the flask up to full volume A. See the teacher for this simulated concentrated standard addition B. Using a squirt bottle bring the flask to volume 4. Using the appropriate technique, mix the standard solution thoroughly Standard Operating Procedure (SOP) – Delivering Titrant from a Burette Operation 1. Take an eye level reading of the initial titrant level and record 2. Deliver the amount of titrant required to satisfy the exercise (Determined by the teacher) 3. Ensure there are no droplets remaining at the delivery point upon completion 4. Record the new level and report to the teacher

Standard Operating Procedure (SOP) – Double pan/Double beam Balance Operation - Using a balance certified for use 1. Tare out a clean weighing boat using the left pan 2. Transfer some of the required chemical (table salt) to a second weighing boat 3. Using the appropriate tools and technique A. Weight out the required amount of chemical B. Dispose of the excess chemical appropriately Standard Operating Procedure (SOP) – Making a Standard Solution Volumetric Standard 1. Rinse and empty a select volumetric flask 2. Bring the volumetric flask up to most of its volume (short of throat) 3. Prepare to add the applicable amount of standard and bring the flask up to full volume A. See the teacher for this simulated concentrated standard addition B. Using a squirt bottle bring the flask to volume 4. Using the appropriate technique (inversion/shale) to mix the standard solution thoroughly Standard Operating Procedure (SOP) – Delivering Titrant from a Burette Operation 1. Take an eye level reading of the initial titrant level and record 2. Deliver the amount of titrant required to satisfy the exercise (Determined by the teacher) 3. Ensure there are no droplets remaining at the delivery point upon completion 4. Record the new level and report to the teacher