SnitchSeeker.com - View Single Post - Potions Lesson 2

hermygirl · 11-24-2019, 10:41 PM

So far, so good. No one had tried to poison themselves yet.

As the first few started to collect their equipment from the side bench, Noble did likewise. Once he returned to the front, he started with the instructions for the next step. “To test the concentration of toxin, we’ll be doing a titration.” Hopefully some of them recognised the term. “First, we need to set up the burette.” He picked up the glass tube with volume markings on. “The tap goes at the bottom, and you’ll see it’s marked with millilitre measurements with 0 at the top, and 50 at the bottom. Carefully clamp the tube into the stand, tightening the grip gently so it has a good hold on the glass.” He did so with his own set up, before looking back to the students. “Now we need to fill the burette. Before doing anything, check the tap is closed. For these burettes, that means the hand being horizontal.” He turned the handle of his tap to show them. “Now, pour antidote into the top of the burette. It might be easier for you to put it on your chair, so you can see what you’re doing.” Noble was tall enough he didn’t need to. “You don’t need to go all the way to the top. To between the 30 and 40 ml mark should be fine…just make sure to write down where the meniscus is starting.”

“When you’ve done that, get a conical flask, and add 50 millilitres of our sample of toxin from this bottle.” Noble retrieved a bottle marked with a skull symbol from the locked cupboard under his desk, measuring out 50ml into his conical flask before leaving the rest of the bottle for the students to come take from. “Add three drops of the Kuznetsov indicator and swirl gently to mix. It should be bright pink, from the toxin. Our aim is to add drops of antidote using the burette to work out how much is needed to cause the colour change and neutralise the toxin.” He added the indicator to his flask, and it soon turned a vivid pink colour. “We’re going to do this part twice. First, we’ll do a rough titre. This means we’ll add around one millilitre of antidote at a time, to get a rough idea of how much antidote we need. Open the tap, watch the meniscus until you’ve added 1ml, and then close the tap. Give the conical flask a swirl, and check the colour. Keep doing this until the colour changes.” He demonstrated, doing repeating this action until the colour turned to green. “So…I took 10ml to change colour. This means that next time, I can let the burette flow for 9ml, and then go drop by drop to accurately determine the amount of antidote needed. Does that make sense?”

He looked around the class for a moment, giving them chance to process what he’d just said. It was a lot, he knew. “You can start with your rough titre now.”

ooc note: Confused? This video might help.

11-24-2019, 10:41 PM	#43 (permalink)
hermygirl Chizpurfle Join Date: Mar 2006 Location: underwater Posts: 10,319 x9	Stuck inside with Sirius \| Splish-Splash \| bamBAM \| ☁ Spooktacular ☁ So far, so good. No one had tried to poison themselves yet. As the first few started to collect their equipment from the side bench, Noble did likewise. Once he returned to the front, he started with the instructions for the next step. “To test the concentration of toxin, we’ll be doing a titration.” Hopefully some of them recognised the term. “First, we need to set up the burette.” He picked up the glass tube with volume markings on. “The tap goes at the bottom, and you’ll see it’s marked with millilitre measurements with 0 at the top, and 50 at the bottom. Carefully clamp the tube into the stand, tightening the grip gently so it has a good hold on the glass.” He did so with his own set up, before looking back to the students. “Now we need to fill the burette. Before doing anything, check the tap is closed. For these burettes, that means the hand being horizontal.” He turned the handle of his tap to show them. “Now, pour antidote into the top of the burette. It might be easier for you to put it on your chair, so you can see what you’re doing.” Noble was tall enough he didn’t need to. “You don’t need to go all the way to the top. To between the 30 and 40 ml mark should be fine…just make sure to write down where the meniscus is starting.” “When you’ve done that, get a conical flask, and add 50 millilitres of our sample of toxin from this bottle.” Noble retrieved a bottle marked with a skull symbol from the locked cupboard under his desk, measuring out 50ml into his conical flask before leaving the rest of the bottle for the students to come take from. “Add three drops of the Kuznetsov indicator and swirl gently to mix. It should be bright pink, from the toxin. Our aim is to add drops of antidote using the burette to work out how much is needed to cause the colour change and neutralise the toxin.” He added the indicator to his flask, and it soon turned a vivid pink colour. “We’re going to do this part twice. First, we’ll do a rough titre. This means we’ll add around one millilitre of antidote at a time, to get a rough idea of how much antidote we need. Open the tap, watch the meniscus until you’ve added 1ml, and then close the tap. Give the conical flask a swirl, and check the colour. Keep doing this until the colour changes.” He demonstrated, doing repeating this action until the colour turned to green. “So…I took 10ml to change colour. This means that next time, I can let the burette flow for 9ml, and then go drop by drop to accurately determine the amount of antidote needed. Does that make sense?” He looked around the class for a moment, giving them chance to process what he’d just said. It was a lot, he knew. “You can start with your rough titre now.” ooc note: Confused? This video might help. __________________