How to use a burette

ISU Gen Chem Lab Tutorials

18 Jun 201704:40

EducationalLearning

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TLDRThis tutorial introduces the proper use of a burette in a chemistry lab setting. It details the parts of the burette, including the tip, stopcock, and barrel with its graduations. The script guides through the cleaning and rinsing process using deionized water and the solution to be used. It explains how to fill the burette and operate the stopcock for precise liquid flow control. The video also demonstrates how to read the volume accurately, calculate the volume delivered during an experiment, and the correct procedure for cleaning and drying the burette after use.

Takeaways

🧪 The burette is a laboratory instrument used for precise dispensing of liquids, and it consists of a tip, stopcock, and a barrel with graduations.
💧 The cleaning process involves pouring deionized water into the barrel, rotating the burette to coat the insides, and then draining the water.
🔄 Rinsing the burette with deionized water is essential before using it with a specific solution to avoid contamination.
🍶 To rinse with the solution, follow the same steps as cleaning, repeating the process two more times with small volumes of the solution.
📦 Filling the burette can be done by pouring directly or using a funnel for ease and accuracy.
📌 The stopcock's position controls the flow of liquid; perpendicular for closed, parallel for open, and in between for fine control.
👀 When reading the burette, ensure you are at eye level with the meniscus to avoid parallax error.
📏 Readings should be taken at the initial and final stages of the experiment, noting the volume between specific graduation marks and estimating to the hundredths.
⚖️ The volume delivered in the experiment is calculated by subtracting the initial volume from the final volume.
🚰 After the experiment, the solution should be drained, and the burette cleaned with deionized water.
🔨 Proper storage of the burette involves hanging it upside down with the stopcock open to dry efficiently.

Q & A

What is the purpose of a burette in a chemistry lab?
-A burette is used to deliver precise volumes of liquid during titration experiments.
What are the three main parts of a burette mentioned in the script?
-The three main parts of a burette are the tip, the stopcock, and the barrel with graduations.
How should the burette be cleaned before use?
-The burette should be cleaned by pouring deionized water into the barrel, rotating it to coat the insides, and then draining the water into a waste container. This process should be repeated with two additional small volumes of water.
What is the purpose of rinsing the burette with the solution before use?
-Rinsing the burette with the solution ensures that any residual water does not dilute the solution being dispensed, maintaining the accuracy of the experiment.
How many times should the burette be rinsed with the solution before filling it for the experiment?
-The burette should be rinsed with the solution two additional times after the initial cleaning.
What are the two methods mentioned for filling the burette with the solution?
-The two methods for filling the burette are pouring the solution directly into the top of the barrel or using a small funnel inserted into the top of the barrel.
Why is it important to remove the funnel before continuing after filling the burette?
-The funnel must be removed to ensure that it does not obstruct the flow of the solution during the experiment.
How can the stopcock be used to control the flow of liquid from the burette?
-The stopcock can be adjusted to be perpendicular to the barrel for full closure, parallel for full opening, or somewhere in between for fine control of the flow rate, allowing for drop-by-drop dispensing or a steady stream.
What is the correct way to read the initial volume in a burette?
-To read the initial volume, one should be eye-level with the meniscus to avoid parallax error and estimate the volume to the nearest hundredth of a milliliter based on the graduations.
How do you calculate the volume delivered in an experiment using a burette?
-The volume delivered is calculated by subtracting the initial volume reading from the final volume reading after the experiment.
What should be done with the burette after the experiment is completed?
-After the experiment, the solution should be drained out, the burette should be cleaned with deionized water, and then it should be hung upside down with the stopcock open to dry efficiently.

Outlines

00:00

🧪 Introduction to the Burette and Its Parts

This paragraph introduces the topic of the video, which is the use of a burette in a chemistry lab setting. It describes the physical components of the burette, including the tip, stopcock, and barrel with its graduations. The zero and fifty milliliter marks are highlighted, indicating the range of the burette. The importance of cleaning and rinsing the burette before use is also emphasized, with a step-by-step guide provided for this process.

💧 Cleaning and Rinsing the Burette

This section provides a detailed procedure for cleaning and rinsing a burette. It begins with the use of deionized water to clean the burette, ensuring the stopcock is closed and the burette is turned almost horizontally to allow the water to flow towards the top. The burette is then rotated to coat the insides, followed by draining the water into a waste container. This cleaning step is repeated three times. After cleaning, the burette is rinsed with the solution to be used in the experiment, and this rinsing process is also repeated three times to ensure no contamination.

📚 Filling and Securing the Burette

The paragraph explains how to fill the burette with the solution for the experiment. Two methods are presented: pouring directly from a container or using a small funnel to aid the process. It advises to remove the funnel before proceeding and to secure the burette upright with a clamp once filled. The focus is on ensuring the burette is ready for accurate dispensing of the solution.

🔬 Operation of the Burette's Stopcock

This section delves into the operation of the burette's stopcock, which is crucial for controlling the flow of liquid. It explains that when the stopcock is perpendicular to the barrel, it is fully closed, and when it is parallel, it is fully open. The paragraph also describes how positioning the stopcock in between allows for fine control over the flow rate, enabling both slow drop-by-drop dispensing and a fine steady stream of liquid.

📏 Reading the Burette's Volume

The paragraph instructs on how to read the initial and final volumes of the burette accurately. It emphasizes the importance of being eye-level with the meniscus to avoid parallax error and provides a step-by-step guide on how to read the volume, including estimating to the hundredths place. The initial and final readings are given as examples, and the method to calculate the volume delivered during the experiment is explained.

🧼 Post-Experiment Burette Care

The final paragraph outlines the steps to be taken after the experiment is completed. It advises allowing the solution to fully drain from the burette, including the tip, and then cleaning it with deionized water as before. The burette should then be hung upside down with the stopcock fully open to dry efficiently, ensuring it is ready for future use.

Mindmap

Keywords

💡Burette

A burette is a piece of laboratory equipment used for accurately measuring and dispensing variable volumes of liquid. It is a tall, slender glass tube with a stopcock at the bottom to control the flow. In the video, the burette is central to the tutorial, as it is used to teach students how to measure and dispense solutions precisely, which is crucial for conducting accurate chemical experiments.

💡Stopcock

The stopcock is a valve-like mechanism located at the bottom of the burette that controls the flow of liquid. It can be adjusted to allow the liquid to flow drop by drop or in a steady stream. In the script, the stopcock is described as being perpendicular to the barrel when fully closed and parallel when fully open, allowing for fine control over the liquid flow during experiments.

💡Barrel

The barrel of a burette is the main glass tube that holds the liquid. It is marked with graduations to indicate volume measurements. In the video, the barrel is described as having a zero milliliter mark at the top and a fifty milliliter mark at the bottom, which helps in reading the volume of liquid accurately.

💡Graduations

Graduations on a burette are the markings that indicate the volume of liquid in the barrel. They are crucial for precise measurement and are used to read the initial and final volumes during an experiment. The script mentions that the burette's barrel is marked with graduations, which are used to read the volume delivered in the experiment.

💡Cleaning

Cleaning a burette is an essential step before using it to ensure that there is no residue from previous chemicals that could contaminate the experiment. The script describes a three-step cleaning process involving rinsing the burette with deionized water to coat the insides and remove any contaminants.

💡Rinsing

Rinsing the burette is a process similar to cleaning but uses the solution that will be dispensed during the experiment. This step helps to remove any remaining water and ensures that the solution being measured is not diluted. The script outlines a rinsing process identical to the cleaning step, which is repeated two additional times with the solution.

💡Filling

Filling the burette involves transferring the solution from a container into the burette's barrel. The script provides two methods for filling: pouring directly into the top or using a small funnel for easier and less error-prone transfer. Proper filling is important to ensure accurate volume measurements.

💡Meniscus

The meniscus is the curved surface of a liquid in a container, caused by the surface tension of the liquid. When reading the volume in a burette, the meniscus must be taken into account to avoid parallax error. The script describes how to read the initial and final volumes by positioning oneself eye-level with the meniscus and estimating to the hundredths place.

💡Volume Delivery

Volume delivery refers to the amount of liquid dispensed from the burette during an experiment. It is calculated by subtracting the final volume reading from the initial volume reading. The script provides an example of how to calculate the volume delivered in an experiment by taking the difference between the initial and final readings.

💡Parallax Error

Parallax error is a common issue in reading measurements from a burette or other laboratory equipment. It occurs when the viewer's line of sight is not perpendicular to the scale, leading to inaccurate readings. The script instructs viewers to position themselves eye-level with the meniscus to avoid this error.

💡Drain

Draining refers to the process of allowing the liquid to flow out of the burette, either during the cleaning process or at the end of an experiment. The script mentions draining the rinsing water into a waste container and later allowing the solution to fully drain out before cleaning the burette.

Highlights

Introduction to ISU Gen Chem Lab Tutorials and the lesson on using a burette.

Description of the parts of a burette: tip, stopcock, and barrel with graduations.

Explanation of the zero and fifty milliliter marks on the burette.

Process of cleaning the burette using deionized water and the stopcock's closed position.

Technique to coat the insides of the burette with deionized water by rotating it.

Instructions for rinsing the burette with deionized water multiple times.

Rinsing the burette with the solution to be used in the experiment.

Two methods for filling the burette: pouring directly or using a funnel.

Importance of removing the funnel before continuing after filling the burette.

Securing the burette upright using a clamp for stability.

Operation of the stopcock for controlling the flow of liquid.

Fine control of flowrate by adjusting the stopcock's position.

Reading the initial volume of the burette by eye-level positioning to avoid parallax error.

Recording the initial volume with estimation to the hundredths place.

Reading the final volume after the experiment and estimating to the hundredths place.

Calculating the volume delivered in the experiment by the difference between initial and final readings.

Post-experiment steps: draining, cleaning, and drying the burette.

Efficient drying method by hanging the burette upside down with an open stopcock.

Transcripts

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