Module 2 Solution Prep

hi everyone and welcome to module two for chy 114. today we are measuring the where we're looking at conductivity and ph those are all hopefully discussed pretty well in your pre-lab and so we're going to go through the procedure today one thing that wanted to note for you to start off is you know those pre-lab notebook templates that we make you do before you come to lab you probably think well those are just busy work these are just my instructors making me do something before come these are real things that scientists actually use in lab this ph in conductivity lab is one that i've been performing for years i've been watching students perform it for years but in order to come in and go through my procedure today still made sheet of everything that i'm going to be doing yes could flip through the procedure in the manual but that procedure in the manual doesn't do things like tell me the amount of grams that i'm going to need in order to make my solutions and it's flipping through whole bunch of different pages and so what was able to do was to take that procedure and condense it into one page of something that can use you'll notice that i'm not going to be using the procedure from the lab manual today at all everything that need in order to complete this lab today is right on this sheet and so just wanted to point that out to you that that is real thing that those notebook templates that that pre-lab part is something that scientists really do when when they're getting ready to perform some sort of lab as they they write out things that they are going to do within that lab and within that experiment so let's go ahead and get started the first thing that we have to do today is to create whole bunch of different solutions and so like said i've already done the calculations as you've done for your pre-lab activities for what the mass is of the various solids that i'm going to need in order to make my solutions the first one that need to make is 100 milliliters of 0.025 molar ammonium nitrate solution and so i'm going to use volumetric flasks in order to make my solutions plyometric flasks look like this don't think we introduce those in module 0. the whole idea of volumetric flask is really this is this little guy's only purpose for existing is for making 100 milliliters of solution and so you can't see it from where you are but encourage you to maybe just google and look one up but there's little line right here and that line marks 100 milliliters and so what i'm going to do is mask out the amount of ammonium nitrate that calculated needed which was 0.200 grams for 100 milliliters of 0.025 molar solution i'm going to mask out that amount and then i'm going to add little bit of water in here halfway up the bulb or so then i'm going to pour in my actual solid and then i'm going to fill up with water up to the line and then at that point will have 100 milliliters of 0.025 molar solution and so let's go ahead and do that so my balance here is started and ready to go i'm gonna go ahead and zero it tear it out get my wave paper and get that ready put my white paper on the balance tear the balance again so it's ready to go here i've got my ammonium nitrate solid well for some of you caught me i'm missing very an important safety element here let me go get some gloves almost forgot and hope some of you caught that as you were watching the video now i'm safe and ready to go so here's my ammonium nitrate solid need 0.200 grams of that so i'm using this scoopula and it's very easy to overshoot and we do want these solutions to be as close to the molarity as we possibly can so almost there right on at point two zero zero grams of ammonium nitrate and so like said i'm just going to add in little bit of water now into the volumetric flask this is not the most efficient way to do it by the way through this water bottle but i'm stubborn and that's how i've started so that's what i'm going to keep doing so i've got little bit of water in there now now i'm going to take my solid remember when we looked at module 0 on ways that we use the balances i've already i've creased my white paper nicely so that can now just dump my solid in there what i'm going to do now you can't see it but there's little bit of solid left in the crease here so i'm just taking my water bottle and squirting that down in keeping the crease so everything flows down into the flask so now have my solid in here as well so i'm going to just now fill up to the line i'm going to use the water bottle to just squirt down the sides make sure that any solid that might have might be sticking to the sides of the flask is actually rinsing down in again it certainly isn't the most efficient way but by using water bottle like this it makes it easier to not overshoot my line because once fill up the bulb and start getting into the neck the water is going to start to fill fairly quickly the one advantage have though of filling it like this just sort of fill some time and talk as i'm filling this up is that by using the the squirt bottle like this it helps me mix the solution as well and so shouldn't have to do much mixing once this is all in here you'll note that i'm looking at eye level as bring this up to the line now the meniscus is right at my line so here's 100 milliliters now i'm just going to shake this little bit nothing that we use is is that dangerous so actually in order to mix this up little bit i'm also just going to put my thumb over the hole here and just invert this few times now have my 100 milliliters of .025 molar ammonium nitrate solution i've got selection of beakers here which i've already pre-labeled and so i'm going to pour everything as make it right into my beakers and so this is our .025 molar ammonium nitrate and so i'm just going to pour it right in so it'll be ready to go for when we need to use it and then as always it's good lab practice i'm just going to rinse out my flask immediately so that it's all ready to go the next time need it just have way speaker here in front of me so i'm just rinsing the flask out couple of times right into the waste speaker the next solution need to make is 25 milliliters of 0.025 molar calcium chloride i'm going to do the same thing just now have this little itty bitty 25 milliliter volumetric flask but i'm going to go through the same procedure dumped spilled little bit of water onto my balance last time so i'm just going to wipe that off but i'm going to go through the same exact thing i've already calculated that need .069 grams of the calcium chloride so get my weight paper ready zero out the balance that's ready to go find my calcium chloride here it is and need to mass out point zero six nine grams that is not lot it is not going to take much of this to get there so i'm just going to tap it fairly carefully 0.070 pretty darn close it's also good lab practice to never put chemicals back into bottle accidentally did that with ammonium nitrate which won't be big deal but we we don't like to put chemicals back into bottle to avoid cross-contamination so any leftover that have on my scoopula i'm just going to put right into my waste beaker add little bit of water into my flask it won't take nearly as much since i'm only doing 25 milliliters of this solution carefully transfer my solid down in rinse my white paper to get all the solid in there and then fill up to the line visually inspect to be sure that all solid looks like it dissolved and it doesn't look like it did but i'm just going to stir it up here little bit there's my calcium chloride solution transferred into again my previously labeled calcium chloride beaker you'll know and some of some of the things here that that tell you when talk about don't necessarily need to go in your notebook in your notebooks you want to be writing the the things that are actually pertinent to to running the procedure and running the experiment but since you're not here live like to just talk about some of the various lab skills and lab procedures that are important that you are missing out by by not being able to be here and one of the things that wanted to mention is how important it is to be organized in lab like this this this lab involves lot of solution prep and i'm going to end up here with seven different solutions here of different materials different molarities and it's really important that i'm able to know which is which and so took about 10 minutes before even started the video to organize myself to get beakers ready that were appropriately labeled with the different solution types and everything like that that might need so that when was ready to go for the lab it's all right here and didn't have to go searching for it for another beaker to use didn't have to to write and label something as i'm working have beaker that's labeled .025 molar calcium fluoride so when made the solution could dump it right in and so then let's just move on to our next one now i'm making point zero two 25 milliliters of .025 molar sodium carbonate na2co3 so here's my sodium carbonate solid double check the label to be sure that that is what am looking for and previously calculated that need 0.066 grams of this sodium carbonate and did it again accidentally dumped in the excess again not as big of deal in in labs like this and with the experiments we're doing but it is good lab practice to not dump materials back into their container quite bit of material on the sides on this one so again i'm just making sure to squirt down the sides of the flask to get all of the solid down into the solution as mix it up fill up to the line pour my solution into my previously labeled sodium carbonate beaker the last solution that have to make from solid is my 25 milliliters of .025 molar glucose c6h12o6 calculated that need 0.113 grams of the solid to make this solution accidentally put way too much on there put about double what need there we go 0.115 pretty close and there's my glucose solution all ready to go almost out of water in my bottle here so i'm just going to go off camera for moment and fill this back up okay so the next thing that need to do so those are all the solutions that needed to make from solid now need to take some of the nh4nl3 solution the .025 molar the 100 milliliters made and need to use that to dilute some down and make 25 milliliters each of point zero two point zero one five and point 0.01 molar solution so again this is where previously calculated using our c1 v1 equals c2 v2 dilution equation calculated how much of the stock solution how much of the .025 molar would need in order to make each of those solutions and so for the 0.02 molar solution calculated that was going to need 20 milliliters of my stock solution of the .025 molar so i'm just going to use graduated cylinder here and measure out 25 milliliters of my stock solution this is my .025 molar nh4no3 i'm measuring 20 milliliters of this in graduated cylinder now want to get as close as can so i'm going to fill close to the line just by pouring it in but then i'm going to use pipette just to get myself up to the actual one so there's our 20 milliliters again i'm looking to make 25 milliliters total so i'm just going to pour this in to my 25 milliliter volumetric flask carefully because this is small opening in my flask here if can do this without spilling it all over the place will be impressed there and just want to make sure that get all the solution in here so i'm just going to rinse the flask down with little bit of water or sorry rinse the graduated cylinder with little bit of water and then pour that into just to make sure that got all of that initial stock solution i'm still well below my line so that's good and now i'm just going to use my squirt bottle and fill up to the line here so again what did is took 20 milliliters of the .025 molar nh4no3 and diluted that up to 25 milliliters so took 20 diluted it to 25. invert that couple of times and now pour the solution again into my previously labeled point zero two zero molar nh4no3 beaker rinse out my volumetric flask for the next solution the next solution need to make is my point zero one five molar nh4no3 solution for that calculated that would need 15 milliliters of my 0.025 molar solution i'm just going to use my volumetric flat or sorry my graduated cylinder and measure out 15 milliliters of my stock solution pour that 15 milliliters into my volumetric flask and again just rinse out my flask here little bit make sure that i'm getting all of the stock solution that was actually in there and then fill up to my 25 milliliter line last solution is my point zero one zero molar solution so need 10 milliliters of my stock solution for that measure 10 milliliters of the stock solution in the graduated cylinder pour that 10 milliliters into my volumetric flask rinsing out my graduated cylinder and finally fill up to the 25 milliliter line and that's all the solutions that need for the conductivity portion of module two have have .025 molar nh4no3 also have 0.2 or sorry 0.02 molar 0.015 and 0.010 of my nh4n03 so have all of my nh4n3 solutions and also have .025 molar 25 milliliters of 0.25 molar cacl2 na2co3 and c6h12o6 so those are all of the solutions that do need to now go on to measure the conductivity which we will do in the next video really need to find way to get my remote actually work all the time so i'm just going to walk over and stop the video