IGCSE Chemistry Laboratory Apparatus part 1

welcome to igcc chemistry lessons in this video we are looking at common operators found in the chemistry lb in our introduction let us Define what is meant by the term laboratory apparatus laboratory apparatus refer refers to the various tools equipment and instruments used in scientific Laboratories to carry out experiments and research these operators play a vital role in the accuracy and reliability of scientific data ensuring that experiments can be replicated and verified by other scientists in this regard the purpose of this lesson is to explore the sources of heat in the lab and The Operators used to determine volume of liquids and gases in the lab the first source of heat used in the lab is a banson burner a bon burner uses gas to light up a flame this one is a source of heat so it is connected Ed it's got a a gas Source here which is connected to a gas tank and then it has got a gas valve here the one which is used to regulate how much uh uh how much gas should be coming through and then we have the airole here which also can be used to regulate how big the flame is being produced so this gas burner or Benin burner is used as as a heat Source in the absence of flammable materials please take note this one should be used in the absence of flammable materials let's say an experiment is using ethanol so if it is using ethanol then that particular experiment shouldn't be exposed to a Benson burner because it has got some naked Flames a bon B produces a single open gas flame and is used for for heating sterilizing uh and the like how a pansing bner is used it is used alongside what we call a tripod stand a tripod stand has got a wire gas on which you can put anything that you are hitting commonly you we heat things in a beaker so you are going to put things things in a beaker for example you want to heat some water you want to boil some water in the lab so you're going to put water into the beaker and then you set up your Ben and banner like this on the tripod stand and then the wire gaze is put on top so we are saying a laboratory tripod stand is a three-leg platform used to support flasks and beakers during heating another source of heat in the lab is what is known as a hot plate a hot plate is a device that consists of a flat plate attached to an electronic heating mechanism the main aim of a hot plate is to evenly is to evenly heat a substance or sample placed on top of it now this is how a hot plate will look like it has got the heating knob okay it has got the heating knob it has got the speed knob the then it has got the hot plate itself and on top of the hot plate that is when you can physically put whatever it is that you want to heat now judging from this one you need to make a choice based on the experiment that you're are doing what source of heat should I use so that would depend on what materials you are using so if you're using anything flammable then you would rather use a heat sauce if you are using uh something that is if you're using uh anything flammable as as your materials you experiment then you would uh better use a hot plate but nonflammable things you can use a bent Banner but also one advantage that this one has is that it's able to evenly heat but a bent burner will not evenly heat because there will be the beginning of uh the heat let's look at uh the hot plate versus a PR and banner so we are saying the advantage of using a hot plate in place of a bent Banner is that a hot plate does not make use of flammable fuel thereby minimizing the chances of what accidents so a hot plate does not use flammable fuels therefore you minimize chances of accident as opposed to a Bren BR the temperature of the bent burner cannot be determined easily but the temperature of the hot plate get get recorded and displayed in digital format on the indicator attached on the device and can be controlled easily remember we have a noob you can determine how much heat you want uh to be coming uh out and also the speed at which it can be done so that is an advantage so two of the advantages is that a hot plate uh does not use flammable fuels and then we know that the temperature of the hot plate can be controlled but apart from that the also the third one you can add which is not written down here is the fact that a hot plate is able to evenly heat okay evenly heat the material so there are about three advantages that has been mentioned take note of them let us now look at the operators used for measuring volumes so first of all you need to remember that volume is defined as the space occupied within the boundaries of an object in 3D dimensional space it is also known as the capacity of an object okay so how much can you put in something if you have a container how much can that container hold so the how much is actually the volume that we are talking about so the first thing is we have our measuring cylinder we also have our buet then we also have our pipet and then we're going to have uh the graduated uh uh syringe okay so this one is a graduated syringe so these are the operators for measuring volume let us look at how exactly they are used but before we do that let's also look at some supporting apparatus as you are measuring volumes so we have a funel and we are saying a a funel is a conical utensil having a small hole or narrow tube at the Apex and us to channel the flow of a substance into a small mouth container now when we say container we don't just mean the containers of cooking oil the containers of what a container simply means something that can contain a substance so it could be uh even in the lab we can talk about containers we can talk about beers we can talk about test tubes we can talk about burettes we can talk about pipet all those are containers uh with respect to the lab so container is simply something that contains that is able to contain a substance now some containers they are small mouth they are small mouth so how do we putting a liquid inside that container is by using the funel so this funel you can just put it insert it let's say this is the mouth of the container so this is the container that you have so you can just insert it on top of the container and then you start pouring the liquid through here and liquid will be able to go through very important so in simpler terms a funel is used to guide liquids and other substances into containers for example during the filtration process let's look at how to read volume very important as you do your practicals as you do your alternative practical final examinations this aspect is going to be very important so we are saying when you are dealing with uh uh when you are reading volumes from tubular apparatus tubular apparatus such as burettes pipets and measuring cylinders Etc what you are supposed to do is I'm going to explain this in a short one when you have a small a tubular apparatus when you pour in a liquid into this tubular apparatus what is going to happen is the water is going to form a cave or the liquid in general it forms what we call a cave so this cave here so it will be a cave that uh is formed like this it caves inwards and this cave is what we call a meniscus so the cave is called the meniscus so the cave is called a meniscus now this meniscus has got two parts it has got what we call the upper meniscus so we have the upper meniscus and then we have here where it bends at the bottom that one we call the lower meniscus okay so now how do you make the readings the readings are supposed to be taken from the lower meniscus so you don't look at the upper meniscus but you look at the lower meniscus that is where the volume readings are taken let's look at an example here so this is the liquid that was poured into this measuring cylinder right here and remember our operators that are used to measure volume they are graduated meaning there are scales that are marked on them so the first thing that you're supposed to do is you're supposed to figure out how the scale is being uh calibrated so for example I can see this long one here the long one here is 19 then I'm going to check okay if this one is 19 and then this other long one here is 20 so how are these divisions being counted so can I try one so if I say 1920 it's not not going to make sense because the 20 is already here so if one is not working then I'm going to try 0.5 how about if I say this is 19 19.5 okay then again be 20 so 0.5 is not working then let me try 0.1 so if what if this one will be 0.1 this one will be 2 this one will be3 this one will be point 4 this one will be five this one will be 6 this one will be 78 then 0.9 and then 20 so the 0.1 has made sense so you can check it out quickly check it out and see if the divisions now each division can either be one can be 0.1 can be 2 can be anything so never take it for granted that you're just supposed to memorize always check for these things so here you have checked that the calibration is 0.1 so now look at the lower meniscus if you check at the bottom here the bottom is actually the lower miniscus is on 20 so meaning the reading here will be 20 Ms or cub CM now the upper meniscus is slightly somewhere here on top which will be somewhere at 19.8 and this reading here is going to be wrong so if you take the reading from the upper meniscus is going to be wrong the correct reading is supposed to be from the lower meniscus that is what is supposed to be done please take note of this every time you're dealing with any apparatus that is tubular and is able to form the lower a miniscus when you put a liquid always take the readings from the lower meniscus all right let's now look at some of these operators so the first one that we have is a measuring cylinder of course it has got different sizes now we are saying a measuring cylinder is a common operatus found in the lab uh it has markings on its walls from where the volumes are read and this is why we say it is graduated So when you say something is graduated meaning it is marked with a scale so it is used for making approximate please take note it is used for making approximate approximate measurements of volumes of liquids approximate measurements volumes of liquids are taken from the lower meniscus as earlier uh discussed then measuring cylinders are of different sizes then we also have a buet now a buet it has got a tap here and it has got markings so the markings here will begin from zero and they will end all the way up to the 50 that is the most common B type that you're going to have now the way the buet is used is it has to be mounted on a clamp stand so this this this one you're seeing here is a clamp stand so it has to be uh mounted on a clamp stand and then the liquid to be measured it can be put in here okay and this is usually a titration setup but for now what you have to know is a buet if you want to use it to measure volume it has to be mounted on a clamp stand as shown in this diagram now a buret is used for accurate so please be taking note of the differences for the uh for the for the uh for the measuring cylinder we said it is used for measuring approximate for making approximate measurements but for this one we are saying accurate measurements of different volumes of what liquids it can measure small amounts of volume for example a buet can be used to measure exactly 22 cubic cm of a liquid so the bottom line here is this one is used to measure accurate measurements accurate measurements of different volumes of liquids okay so that is a buret it has a scale which starts from 0 cub CM at the top up to 50 Cub CM at the bottom so the scale is more sensitive than the measuring cylinder so when you are carrying out an experiment you need to choose an appropriate an appropriate operatus so if you're looking for accurac you would rather get a buet and not measuring cylinder let's look at a pipet okay so this is a pipet we also have different types of pipets and different sizes of pipets okay so now we are saying a pipet is used for delivering accurately a fixed a fixed volume of a liquid so we started from measuring cylinder a measuring cylinder does approximate measurements of volumes of liquids then we went to the buet a buet measures the accurate measurements then we go to EP pipet the one which we are saying it is used to deliver accurately a fixed volume of a liquid now those are the differences now what do we mean accurately a fixed volume of the liquid if you are using a pipet which is labeled one M meaning it can only measure one mil if you're using a pipet that is labeled 5 mil it can only measure 5 mil nothing less nothing more that's the way it works if you're using the one which is labeled 25 M meaning it can only measure 25 M so when you uh here on the Mark here that is where the 25 is here on the Mark here if you're using a five that is where the five is and then there's also here it is nicely labeled so the one me is actually labeled nicely here now the question is how do you put a liquid into the pipet how to put a liquid into AEP pipet so we use what is known as AEP pipet filler okay we use what is known as AEP pipet filler now the common pipet that you're going to see is has displayed here so this pipet has got parts it has got a here where you are seeing here there's an A and this a is just for air so A is for air and then it has got an S here this s is just for uh is is s valve is used for sucking the liquid okay for sucking the liquid then we have got an e so this e is just for empty okay for empting so now the way it here this this side this other side here that is where you insert the prepet this is where you insert the pepet so what are you going to do you going to insert uh you're going to insert the pipet there you insert it then when you insert the pipet you're going to squeeze the air okay you're going to squeeze the air and then you're also going to squeeze this region here which I I like to call the tmy so you're going to squeeze the tamy here and you squeeze it at the same time a and the tamy you squeeze it at the same time and then this will become flat when it becomes flat and then you're going to insert you're going to insert into the liquid so when you insert into the liquid then you're going to squeeze you're going to squeeze on the S valve when you squeeze on the a valve then the liquid will start getting into what into the pipet that is how it is done okay there's also another simpler version of a pipet which just has a wheel so the procedure is the same here is a pet that is inserted you put it into the liquid you want to draw and then you just start moving the wheel so you start moving the wheel as you are moving the wheel the liquid is coming up so this one is a little bit simpler now we look at the gas syringe so this is called a graduated gas syringe now the volume of the gas can be made can be collected and measured using a graduated measuring operators called a gas syringe so this gas syringe can be used to measure the volume of a gas so a graduated cylinder inverted into water may also be used provided the gas isn't soluble so we have an an alternative here so if you don't have if you don't have the gas syringe then you can also use a graduated cylinder you invert it into water and it will be able to collect the gas but this will be dependent on the nature of the gas if the gas isn't soluble in water then well and good so look out on the uh collection of gases okay look out for the video on the collection of gases so if the gas happens to be heavier than air and is colored the cylinder can be used upright let's look at how this thing is done so you're are going to put a conical flask you're going to make sure it is air tight here as you put the straw okay and connect the syringe so the syringe has got the plunger here and then whatever reaction is producing the gas here the gas will have no choice to escape in the sides because it's airtight it has been sealed so the only place where the gas will go is it will go into this straw and finally get into the what into the uh the syringe now the syringe is going to be pushed by the pressure so as it moves there are readings that are on the on the side here so as if the gas moves as much as here it means here where it has reached that is how much gas has been produced from here if it reaches there then it means that is how much gas has been produced from here because the gas has got nowhere else to go other than just coming through thank you for this lesson look out for part two on other General apparatus