Question Video: Determining How a Test Tube Should Be Held When Heating over a Bunsen Burner | Nagwa Question Video: Determining How a Test Tube Should Be Held When Heating over a Bunsen Burner | Nagwa

Question Video: Determining How a Test Tube Should Be Held When Heating over a Bunsen Burner Chemistry • First Year of Secondary School

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In the diagram, a sample in a test tube is heated over the flame from a Bunsen burner. How and where should the test tube be held? [A] The test tube should be held with bare hands at the end nearest to the flame. [B] The test tube should be held using a piece of paper at the end farthest from the flame. [C] The test tube should be held using gloves at the end nearest to the flame. [D] The test tube should be held using tongs at the end nearest to the flame. [E] The test tube should be held using tongs at the end farthest from the flame.

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Video Transcript

In the diagram below, a sample in a test tube is heated over the flame from a Bunsen burner. How and where should the test tube be held? (A) The test tube should be held with bare hands at the end nearest to the flame. (B) The test tube should be held using a piece of paper at the end farthest from the flame. (C) The test tube should be held using gloves at the end nearest to the flame. (D) The test tube should be held using tongs at the end nearest to the flame. Or (E) the test tube should be held using tongs at the end farthest from the flame.

In this question, a Bunsen burner is being used to heat the test tube and the sample it contains. A Bunsen burner is a device used to heat items in the lab to very high temperatures. The diagram shows the tubing connecting the burner to a gas inlet leading to an air vent, which allows us to control the amount of oxygen entering the burner and thus controlling the temperature of the flame. We can see that the Bunsen burner here is completely combusting with plenty of oxygen since the flame is blue, and thus it is extremely hot. Great care must be taken to safely use the Bunsen burner. We must secure the items that are being heated as well as keeping items that are not glassware or flame-retardant away from the flame of the Bunsen burner.

If we look at answer choices (A), (C), and (D), we can see that these three answer choices suggest that the test tube should be held at a point nearest to the flame. These answer choices can be eliminated since this would be a very unsafe practice, particularly with bare hands. It is worth noting that hot glassware looks identical to cold glassware, and you should never touch glassware with your bare hands if you’re unsure if it is hot or cold.

This leaves us with answer choices (B) and (E). Answer choice (B) suggests that the test tube be held with a piece of paper. When heating glassware, it is important that the glassware is securely held. It is difficult to imagine a secure way to hold a test tube with a piece of paper. Additionally, paper is a very flammable substance, and we would not want to hold it near the Bunsen burner flame. We can eliminate answer choice (B).

This leaves answer choice (E), which suggests using tongs. Using test tube tongs to securely heat the sample in this test tube would be the ideal way to hold the test tube. This would allow us to keep a safe distance from the Bunsen burner flame. And since the tongs are generally metal, they are not flammable and can be safely used to heat glassware. With tongs, we can securely point the test tube away from any people in the lab with us and safely heat the sample. Therefore, the answer to the question “How and where should the test to be held?” is (E). The test tube should be held using tongs at the end farthest from the flame.

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