Common Scientific Glassware and the Undergraduate Chemistry Laboratory
Summary
TLDRThis script introduces essential laboratory equipment for chemistry, emphasizing the importance of using the right tools for various tasks. It covers glassware like beakers, graduated cylinders, and test tubes, and explains their specific uses. It also discusses safety equipment, such as fume hoods, and the correct use of balances for weighing solids. The video aims to familiarize viewers with lab practices for safe and accurate chemistry experiments.
Takeaways
- 🧪 Beakers are versatile glassware used for conducting reactions, transporting solutions, and as water baths for temperature control, and come in various sizes from 5ml to several liters.
- 📏 Graduated cylinders are used for accurately measuring liquid volumes, and readings should be taken from the bottom of the concave meniscus.
- 🔬 Test tubes are small reaction vessels for observing visible changes, requiring a test tube rack for stability and a holder for heating or suspending in water baths.
- 🍶 Erlenmeyer flasks are conical and used for mixing reagents and conducting reactions, with sizes varying and measurements being imprecise.
- 🔬 Buchner flasks, or filter flasks, are similar to Erlenmeyer flasks but have a side arm for vacuum filtration and should not be used for other purposes.
- 🌡️ Spatulas are used for picking up solids, coming in various shapes and should be handled gently to avoid bending.
- 🧪 Stirring rods are for briefly stirring solutions and should not be confused with thermometers, requiring careful handling to prevent rolling away.
- 💧 Pipettes are used for adding small amounts of liquid, operated by squeezing a bulb to draw and release liquid.
- 📊 Burettes are used in titrations, with inverted gradations to measure the volume added to another vessel.
- ⚗️ Volumetric flasks are used for making standard solutions, with a single line indicating the exact volume, and require careful handling near the neck due to rapid filling.
- 🌀 Separatory funnels are used for separating immiscible liquids and require the correct size cap and ring clamp for stability and to prevent spilling.
Q & A
What is the primary purpose of a beaker in a chemistry lab?
-Beakers are used for conducting reactions, transporting solutions and solvents, and as water baths to control the temperature of other vessels.
Why should we not use beakers for precise volume measurements?
-The measurements on the sides of beakers are for estimating volume, but they are not accurate enough for precise measurements, which should be done using more precise glassware.
What is the main function of a graduated cylinder?
-A graduated cylinder is used to measure the volume of a liquid accurately.
How should you read the volume in a graduated cylinder?
-You should read the volume from the bottom of the concave meniscus to avoid ambiguity.
Why are test tubes useful for observing reactions?
-Test tubes are small reaction vessels that allow for the observation of visible changes in reactions, but they require a test tube rack or holder to prevent them from rolling away or being heated safely.
What is the difference between an Erlenmeyer flask and a Buchner flask?
-An Erlenmeyer flask is used for mixing reagents and conducting reactions, while a Buchner flask has a side arm specifically for vacuum filtration.
Why should a Buchner flask not be used for purposes other than filtration?
-The side arm opening of a Buchner flask can cause the liquid to escape if used for other purposes, making it unsuitable for reactions where containment is necessary.
What is the purpose of a separatory funnel?
-A separatory funnel is used for separating two immiscible liquids.
How should you handle a pipette when transferring liquids?
-You should squeeze the pipette bulb to draw the liquid in, release the bulb to fill the pipette, and then transfer the liquid to the new vessel.
What is the role of a burette in a titration process?
-A burette is used to measure and add precise volumes of liquid to another vessel during a titration.
Why is it important to be cautious when using a volumetric flask?
-Volumetric flasks have long necks that can be easily knocked over, and they require careful handling, especially when filling near the neck, to avoid spillage.
What is the purpose of a mortar and pestle in a lab?
-A mortar and pestle are used to crush solid materials into a powder.
What is the significance of the ground glass joint in glassware?
-The ground glass joint is the thickest part of the glassware and should be clamped whenever possible to ensure stability and prevent breakage.
How does a reflux condenser work?
-A reflux condenser works by cooling the gas in the tube, causing it to condense and drip back into the solution, allowing for continuous boiling without loss of volume.
Why is it crucial not to block the top of a condenser?
-Blocking the top of a condenser can cause pressure to build up, which may result in an accident due to the potential for explosion or breakage.
Outlines
🧪 Introduction to Chemistry Lab Equipment
This paragraph introduces the viewer to the essential equipment found in a chemistry laboratory. It emphasizes that real labs differ from their portrayal in media. The narrator begins by discussing the importance of glassware, detailing the uses and sizes of beakers, and explaining their role in conducting reactions, transporting solutions, and serving as water baths. The paragraph also covers graduated cylinders for volume measurements, test tubes and their accessories for observing reactions, and Erlenmeyer flasks for mixing reagents. Specialized glassware like the Buchner flask and funnel, filter funnel, and powder funnel are also introduced, each with specific uses and precautions.
📚 Lab Techniques and Additional Equipment
The second paragraph continues the exploration of laboratory equipment, focusing on tools for handling solids and liquids. Spatulas for picking up solids, stirring rods for mixing, and pipettes for transferring small liquid volumes are described. The paragraph then introduces the burette for titrations and the volumetric flask for preparing standard solutions, highlighting the importance of careful handling to avoid breakage. The separatory funnel and dropping funnel are explained for their roles in liquid separations and controlled additions, respectively. The mortar and pestle for crushing solids and the round-bottom flask for serious reactions are also mentioned, with notes on their use and the necessity of appropriate clamping.
🔬 Advanced Lab Apparatus and Safety
This paragraph delves into more complex laboratory apparatus such as the reflux condenser, which is used for boiling liquids without loss of volume by condensing vapor back into the solution. The importance of not blocking the condenser's top to prevent pressure buildup and potential accidents is stressed. Clamps and a clamp stand for securing glassware are discussed, along with considerations for weight distribution and the various types of clamps available. The paragraph also covers columns for column chromatography, filter paper for various filtration needs, and other small equipment like watch glasses, evaporating dishes, melting point tubes, and NMR tubes. The paragraph concludes with a brief mention of the fume hood, emphasizing the importance of safety equipment and proper disposal practices.
🛡️ Safety and Practical Lab Techniques
The final paragraph wraps up the introduction by stressing the importance of proper equipment usage for safety in the chemistry lab. It mentions the necessity of familiarizing oneself with eye wash or shower stations and appropriate disposal containers, which may vary by lab. The narrator encourages viewers to pay attention to instructions from their instructors regarding these safety features. With the basic information about equipment and safety outlined, the paragraph invites the viewer to move forward and begin learning simple laboratory techniques, indicating that the next steps will involve hands-on experience.
Mindmap
Keywords
💡Beaker
💡Graduated Cylinder
💡Test Tube
💡Erlenmeyer Flask
💡Buchner Flask
💡Separatory Funnel
💡Pipette
💡Burette
💡Volumetric Flask
💡Reflux Condenser
💡Mortar and Pestle
Highlights
Introduction to the essential equipment used in a chemistry laboratory.
Explanation of the practical differences between a real chemistry lab and its portrayal in media.
Overview of glassware, emphasizing the importance of beakers in various sizes for conducting reactions and controlling temperatures.
Discussion on the proper use of graduated cylinders for accurate liquid volume measurements and the technique for reading the meniscus.
Use of test tubes, racks, and holders for observing reactions and heating processes.
Introduction to Erlenmeyer flasks for mixing reagents and conducting reactions, noting their imprecise measurements.
Differentiation between Buchner flasks and their specific use in vacuum filtration.
Utilization of Buchner funnels and rubber adaptors for vacuum filtration setups.
Description of filter funnels and powder funnels for gravity filtrations and adding powders to flasks.
Importance of using spatulas and stirring rods correctly for handling solids and stirring solutions.
Functionality of pipettes for transferring small amounts of liquid.
Explanation of burettes and their use in titrations for measuring added volumes.
Use of volumetric flasks for preparing standard solutions with precise volume markings.
Introduction to separatory funnels for separating immiscible liquids and the importance of correct cap sizing.
Difference between dropping funnels and separatory funnels, especially in reactions requiring controlled addition of liquids.
Application of mortar and pestle for crushing solid materials into powders.
Use of round-bottom flasks in serious reactions, noting their heat distribution and stirring advantages.
Description of reflux condensers for boiling liquids without volume loss and safety precautions.
Importance of clamps and clamp stands for securing glassware during experiments.
Overview of columns used in column chromatography with various designs and features.
Use of filter paper for filtration setups and drying solids.
Introduction to watch glasses and evaporating dishes for holding, weighing, and drying solids.
Functionality of melting point tubes for determining the melting point of compounds.
Use of NMR tubes for obtaining NMR spectra of compounds.
Importance of working within a fume hood and using a combination hot plate and magnetic stirrer for reactions.
Necessity of accurate weighing with scales or balances and the process of taring for precise measurements.
Conclusion emphasizing the importance of understanding and using lab equipment properly for safety and effective chemistry practices.
Transcripts
If we are going to learn how to do chemistry, the first thing we need to do
is learn a little bit about all of the equipment in the laboratory. We are probably familiar with
the way that chemistry labs are portrayed in movies, cartoons, and horrible stock images,
but not surprisingly a real chemistry lab does not look very much like this. Instead, a chemistry
laboratory will typically look something like this. So let’s familiarize ourselves with the
instruments we will be using on a regular basis. First off, if we are going to do chemistry we
are going to have to use lots of glassware. Let’s start with one of the more familiar items. These
are beakers. There is a range of beaker sizes available, ranging from as small as 5 milliliters,
to as large as several liters, and there are different situations in which these different
sizes would be desirable. Most often, we tend to use beakers between around 10 to 400 milliliters.
Beakers have many uses. Reactions can be conducted in them. They can be used to transport solutions
and solvents. Or they can be used as water baths, meaning we can suspend some other vessel
in the beaker in order to control its temperature. Always be aware of what you are using a beaker for
and use the appropriately sized beaker for the job. The measurements on the sides are great
for estimating the volume, but we do not carry out actual measurements of volume using beakers,
we have glassware that is more accurate for measuring volumes when necessary.
Speaking of measuring volumes, next up we have the graduated cylinder. A graduated cylinder
is used to measure the volume of a liquid. These also range quite a bit in size. Be
aware that they are tall, so you may at some point accidently knock one over. In order to avoid this,
always place them down where you can see them or where less movement is occurring. We should also
be aware that when taking measurements with a graduated cylinder, we will always read from
the bottom of this concave meniscus. This word refers to the way the liquid climbs a little
bit up the edges, and to avoid ambiguity, we will take readings from this position here.
Next we have test tubes, test tube racks, and test tube holders. A test tube is a very small reaction
vessel, which is nice to use when observing obvious visible changes in the reaction. They
don’t stand up by themselves so be sure to place them a test tube rack so they don’t roll away.
A test tube holder, like this one, can be used to hold a test tube above the
flame of a Bunsen burner, or suspend it in a water bath. Get comfortable holding one of
these before heating it and be sure to have one that fits the size of test tube you are using.
Next let’s check out another recognizable piece of glassware, the Erlenmeyer flask. A conical,
or Erlenmeyer flask looks like this. These are typically used for mixing reagents together
and conducting a reaction. Again, they come in various sizes, and the measurements on the sides
are quite imprecise, so they shouldn’t be used when accuracy is necessary.
The tapered edges leading to the small opening at the top prevent spilling, and they also make these
flasks ideal for clamping, which is something we will commonly want to do. If the mixture needs
to be manually stirred, you can manipulate them with less fear of the solution escaping
which is why these are typically preferred for running reactions over beakers.
Next we have the indispensable Buchner flask, or filter flask. These are very similar to the
Erlenmeyer flask, it is simply that the Buchner flask has a side arm which is used when conducting
vacuum filtration, which we will discuss in another tutorial. Avoid using these for anything
other than filtrations as the side arm opening can cause the liquid to escape.
With the Buchner flask covered, let’s check out the Buchner funnel and accompanying
rubber adaptor. The Buchner funnel is also used when conducting vacuum filtrations.
These sit in the Buchner flask and are typically made of ceramic, but plastic
ones are sometimes used. For a better seal, we tend to use the rubber adaptor. These aren’t
all that stable so be sure to clamp the flask first before assembling the filtration setup.
Next let’s examine the filter funnel. For gravity filtrations, we use this kind of funnel.
Either cotton wool or a folded piece of filter paper can be used for gravity filtrations,
which will also be properly demonstrated later.
To finish off the funnels, let’s check out the powder funnel. When wanting to add powder to a
flask, which could be a drying agent, or any solid reagent, sometimes it is much easier to
use a powder funnel.These can be placed on top of a flask, and a solid can be added easily.
These typically are not made of glass so they are easily distinguishable from the other funnels.
Be sure to check and see if it is clean before using it and clean it afterwards.
Next we have the spatula. When picking up solids, we will use a spatula. Some are curved,
some are flat, and they usually bend if necessary, but be gentle whenever possible.
Similarly we have the stirring rod. When wanting to briefly stir something,
a stirring rod is the best option. Do not get this confused with a thermometer, and be careful when
putting these down as they do roll away. Then we get to the pipette. For adding
small amounts of liquid, we use a pipette. Using a pipette bulb,
a liquid can be taken up and put somewhere else. Simply squeeze, place into the liquid,
release the bulb to draw the liquid into the pipette, and then transfer it to the new vessel.
Next up we have the burette. These are commonly used with titrations. Like a graduated cylinder,
it has these gradations for measuring volume, but unlike a graduated cylinder they are inverted,
so that you can measure how much volume is being added to some other vessel.
A more thorough demonstration of this instrument will be shown when we conduct a titration.
Then there is the volumetric flask. When making standard solutions, we use a volumetric flask.
Much like the volumetric pipette, a single line indicates the exact volume of this flask. Because
of the long necks, these can be knocked over, so like the graduated cylinders, be careful where you
place them. Also check which cap you have, as some fit nicely but others are deceptive. When
using these to make solutions, be extra careful once you reach the neck, as this will fill up much
more rapidly than the bulb, as it is so narrow. Moving along, we find the separatory funnel,
which we learned about when going over extraction in the organic chemistry series. For separating
two immiscible liquids, we will use a separatory funnel, sometimes abbreviated as a sep funnel.
When using these, make sure you have the correct size cap so that nothing spills when inverted.
Sep funnels require a ring clamp, so make sure that the size of your ring clamp is appropriate,
as if too small the funnel will be unstable, but if too big, it will not hold the funnel at all.
We will notice that the separatory funnel has a valve for releasing liquid.
Sometimes the valve comes assembled, and sometimes they need to be assembled. We will talk more about
this apparatus when we perform an extraction. Now this is called a dropping funnel. A dropping
funnel looks very similar to a sep funnel, but they have this separate arm and a ground
glass joint. These joints become important when conducting reactions under nitrogen or
argon atmosphere with air-sensitive reagents and products. They are used to control the addition
of a liquid to a reaction, and the arm keeps the pressure constant, so the addition is smooth and
continuous. If there is no need for the ground glass joint, a sep funnel will often suffice
as a dropping funnel, but it is good to know what this is if you come across one.
Next we find the mortar and pestle. If you need to crush up some solid material into a powder,
you’d use a mortar and pestle. These are pretty simple, you simply put the material in the mortar,
and crush it with the pestle. These are usually ceramic and quite heavy, and they are fun to use.
Now we get to that ubiquitous piece of glassware for the organic chemist, the round-bottom flask.
As we will come to see, for more serious reactions, we will use a round-bottom flask.
There are many sizes, and they almost always have at least one ground glass joint in them.
The roundness allows for better heat distribution and stirring,
where the joints allow for easy fitting with other glassware. Since they don’t stand on their own,
we will use a cork ring to hold them up, which must be of an appropriate size.
If securing to a solid support, be sure to clamp them around the ground glass joint area
as this is where the glass is the toughest. To be clear, this goes for all glassware,
the ground glass joint is the thickest part and should be the area clamped whenever possible.
Moving along, this is a reflux condenser. When we want to boil a liquid, but don’t want to lose any
of the volume, we will use a reflux condenser. These can look very different from one another,
but they are all used the same way. They are essentially a tube with a jacket, although some
are just a tube, but these are less reliable. The glass jacket is filled with water through these
side arms which cools the environment in the tube, allowing for the gas to condense and drip back
into the solution. In this way, the liquid is always boiling, but never escapes the reaction
vessel. Tubes are attached to the arms here, with water flowing in from the bottom and out the top
through a separate tube. It is very important to mention, that we must never block the top of the
condenser with anything, as this will cause the pressure to build up, which could result in an
accident. A more thorough demonstration of this apparatus will be conducted later.
Here we have some clamps and a clamp stand, something we’ve already seen a few times by
now. As you have likely gathered, these are used to hold up glassware and keep them locked
in place. When using these, be careful with the weight distribution as we don’t want the clamp
stand to topple over. The base may jut out in one direction more than another, so don’t overload one
side when possible. Clamps themselves are very adjustable with several screws, and there are
a few different styles in terms of precisely how they grip the glassware. Familiarize yourself with
these as we should know what kind of clamp will work best with a particular piece of glassware.
Now here, this lovely instrument is a column. We use these when performing column chromatography.
They are essentially big, long, glass tubes with a valve at the bottom.
Some have a ground glass joint at the top, and some have solvent reservoirs. Some have a frit
at the bottom, which is a porous material, and some don’t. We will learn how to assemble
and use one of these in a later tutorial, but for now we know what they look like.
Now getting to some of the smaller accoutrements, this is filter paper. Filter paper comes in
various sizes and gradings depending on the size of the particles you are filtering.
Generally speaking, a finer grading will filter a solution more slowly.
Filter paper will be used for the Buchner filtration setup
but can also be used for gravity filtrations, which we will perform later in the series.
Filter paper can also be used to passively dry solids as they tend to absorb liquids.
Now this is a watch glass. A watch glass is just a simple piece of glassware that can be
used to hold and weigh an amount of solid. They wobble a bit, so be gentle with them.
Similarly, this is an evaporating dish. Sometimes you may need to let a wet solid sit and dry.
We can use an evaporating dish for this. They are typically ceramic and have high edges.
Now this little thing is a melting point tube. When performing melting point determination,
you need a melting point tube. These look like little capillaries but they are in fact sealed at
one end. They are very thin and small so make sure you have an area where you can safely place them.
Solid is added to the open end, and the tube can be placed in any melting point apparatus
when measuring the melting point of a compound. In the same vein, here is an NMR tube and cap.
When you need to obtain an NMR spectrum, this is the tube we will use, and here is the cap
we use. Simply make a rather concentrated solution of the compound you’d like to run,
add it to the tube with a pipette, and then cap it. This is now ready for the spectrometer.
Now let’s head over to the fume hood. We will tend to run reactions in here, so many
instruments will live inside the hood. This is a combination hot plate and magnetic stirrer.
As one would guess, this piece of equipment can both heat and stir your reaction. One dial will
control the heat, and the other will control the rotational speed of the magnetic stir bar.
The heating may need to be calibrated as the dial may not be totally accurate.
Some have a plug for an external thermometer to be used so keep an eye out for that. As
for the stirrer, a small Teflon stir bar can be placed in the solution and the contents
of the reaction flask will be mixed, like so. The stirring can get quite aggressive,
so be sure to clamp up the vessel to stop it from possibly falling over.
Another indispensable piece of equipment is the scale, or balance. Scales are used to weigh the
mass of solids accurately. Be sure to tare the scale with any vessel you are weighing.
What this means is that whatever will hold the solid, we can place it on the balance
and zero the mass, so that the measurement we take correlates precisely with the solid that is added.
Make sure to avoid pouring or scooping the solid onto the vessel while it is on the scales,
as any residual material may cause the expensive scales to break or malfunction. Take the vessel
off the scale each time you want to add or remove solid from the vessel you are using.
And that wraps up an introduction to the equipment you are most likely to use in the
chemistry laboratory. Knowing how to use this equipment properly is the best way to stay safe
while doing chemistry, in addition to becoming familiar with any eye wash or shower stations,
and appropriate disposal containers. These will be specific to your lab,
so be sure to pay attention when instructed on how to use these by your own instructor. But
with this basic information understood, let’s move forward and start learning some simple techniques.
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