Question

To prepare a sample in a capillary tube for a melting point determination, gently tap the tube into the sample with the_____________
a) open,
b) closed end of the tube down.
Continue tapping until the sample____________
a) completely fills the tube
b) is a couple millimeters high,
c) has a single crystal in the tube.
Then, with the _________
a) closed,
b) open end of the tube down,
tap the sample down slowly or ________
a) heat the tube up,
b) drop the tube into a longer tube,
c) shake the tube in the air to move the sample down faster.

Answer 1

Answer:

1. A

2. B

3. A

4. B

Explanation:

In Chemistry, one of the ways to test for the purity of a substance is to determine its melting point. Generally, a pure substance has its melting point between the temperature range of 1 - 2 (°C). In order to determine the melting point of a substance, we can use the procedure stated below;

To prepare a sample in a capillary tube for a melting point determination, gently tap the tube into the sample with the open end of the tube down. Continue tapping until the sample is a couple millimeters high. Then, with the closed end of the tube down, tap the sample down slowly or drop the tube into a longer tube. Lastly, you should ensure that you can see some or perhaps all of the sample in the viewfinder (magnifier) when it is placed on the melting point apparatus, then you can turn on the heat.

Additionally, in taking your readings, you should record the temperature for when the melting starts to when it ends.