A Guide to Burettes and How to Read Them

A burette is a device that can accurately measure and deliver small volumes of liquids in a laboratory. It is commonly used in titrations, which are experiments that involve adding a solution of known concentration (the titrant) to another solution of unknown concentration (the analyte) until a chemical reaction occurs. The point at which the reaction occurs is called the endpoint, and it can be observed by a change in color or pH.

Table of Contents

Parts of a Burette

The burette is used to add a known volume of the blue solution to the flask. The stopcock is opened and the blue solution is allowed to flow into the flask. As the blue solution is added, the indicator changes color. The color change indicates that the reaction is complete.

The burette is a valuable tool for titrations. It allows scientists to accurately measure the volume of a liquid, which is essential for accurate results.

Here is a more detailed description of the parts of a burette:

Buret: The buret is typically made of glass or plastic. It is graduated in milliliters (mL) or cubic centimeters (cm³). The graduations on the buret are used to measure the volume of the liquid.
Buret clamp: The buret clamp is used to hold the buret in place. It is typically made of metal or plastic.
Burette Stopcock: The stopcock is used to control the flow of liquid from the buret. It is typically made of glass or plastic.
Flask: The flask is typically made of glass or plastic. It is used to hold the solution of unknown concentration.
Acid or base and indicator: The acid or base is used to react with the solution of unknown concentration. The indicator is used to determine the point at which the reaction is complete.

How to Use a Burette

A burette is a piece of laboratory equipment used to measure the volume of a liquid. It is typically used in titrations, which are a type of chemical analysis that involves adding a known volume of a solution of known concentration to a solution of unknown concentration until the reaction is complete.

To use a burette, follow these steps:

Clean and dry the burette. Rinse the burette with the solution that you will be using, and then dry it with a clean towel.
Fill the burette with the solution. Use a funnel to fill the burette with the solution. Make sure that the solution is above the zero mark on the burette.
Clamp the burette to a stand. Use a burette clamp to secure the burette to a stand.
Open the stopcock. Turn the stopcock to open it.
Add the solution to the flask. Slowly add the solution to the flask, allowing it to flow down the side of the flask.
Close the stopcock. Turn the stopcock to close it.
Read the burette. Read the volume of the solution that has been dispensed.

Here are some tips for using a burette:

Use a burette that is the correct size for the volume of solution that you need to measure.
Make sure that the burette is clean and dry before use.
Use a funnel to fill the burette to prevent spills.
Open the stopcock slowly to prevent the solution from splashing out of the burette.
Read the burette at eye level to avoid parallax errors.

Using a Burette in a Titration

A burette is typically used in a titration to add a known volume of a solution of known concentration to a solution of unknown concentration. The solution of known concentration is called the titrant, and the solution of unknown concentration is called the analyte.

To use a burette in a titration, follow these steps:

Add the analyte to a flask. The analyte should be placed in a flask that is large enough to accommodate the volume of titrant that will be added.
Add a few drops of indicator to the analyte. The indicator will change color when the reaction is complete.
Fill the burette with the titrant. The titrant should be placed in a burette that is the correct size for the volume of titrant that will be needed.
Clamp the burette to a stand.
Open the stopcock and slowly add the titrant to the analyte. Add the titrant until the indicator changes color.
Record the volume of titrant that was added.

The volume of titrant that was added is used to calculate the concentration of the analyte.

Here are some additional tips for using a burette in a titration:

Make sure that the indicator is compatible with the titrant and analyte.
Add the titrant slowly to avoid overshooting the equivalence point.
Record the volume of titrant that was added to the nearest 0.01 mL.

Troubleshooting

If you are having trouble using a burette, here are a few things to check:

Make sure that the burette is clean and dry.
Make sure that the burette is the correct size for the volume of solution that you need to measure.
Make sure that the stopcock is open when you are adding solution to the flask.
Make sure that you are reading the burette at eye level.

How to Read a Burette

To read a burette, you have to look at the bottom of the meniscus, which is the curved shape of the liquid surface. The meniscus forms because of the attraction between the liquid and the glass and the cohesion of the liquid molecules. For most liquids, like water, the meniscus is concave (curved downward), and you have to read the lower part of the curve. For some liquids, like mercury, the meniscus is convex (curved upward), and you have to read the upper part of the curve.

To read a burette, follow these steps:

Find the zero mark. The zero mark is the point on the burette where the volume is 0 mL.
Identify the meniscus. The meniscus is the curved surface of the liquid in the burette.
Read the volume from the meniscus. The volume is read from the bottom of the meniscus.

Tips for Reading a Burette

Make sure that the burette is clean and dry. A dirty or wet burette can make it difficult to read the meniscus.
Use a flashlight or other light source to illuminate the meniscus. This can make it easier to see the meniscus.
Hold the burette at eye level. This will help to avoid parallax errors.

Reading the Burette in the Image

The image shows a burette that is filled with a blue solution. The zero mark is located at the bottom of the burette. The meniscus is the curved surface of the blue solution. The volume of the solution is read from the bottom of the meniscus. In this case, the volume is 19.62 mL.

Additional Tips

When reading a burette, it is important to read the volume to the nearest 0.01 mL. This is because the volume of the solution can be very small.
If the meniscus is difficult to read, you can use a piece of paper or a ruler to help you. Place the paper or ruler behind the burette so that you can see the meniscus more clearly.

How to Perform a Titration

When you perform a titration, you have to record the initial reading of the burette, which is the volume of the titrant solution before any is added to the analyte solution. Then, you have to open the stopcock valve and let some of the titrant solution drip into the analyte solution until you reach the endpoint. You have to swirl or stir the analyte solution constantly to ensure that it mixes well with the titrant solution. You also have to watch for any color change or pH change that indicates that the endpoint has been reached. When you reach the endpoint, you have to close the stopcock valve and record the final reading of the burette, which is the volume of the titrant solution after all has been added to the analyte solution.

The difference between the final reading and the initial reading is called the titre, and it represents the volume of the titrant solution that was required to react completely with the analyte solution. You can use the titre to calculate the concentration of the analyte solution, if you know the concentration of the titrant solution and the equation of the reaction.

References: britannica.com, en.wikipedia.org