What are the reasons to determine the melting point of a sample in a melting point apparatus? Select one or more: A. U Assessment of the sample's purity
B. Conversion of the solid sample to liquid
C. Identification of an unknown sample
D. Removal of impurities from the sample
To prepare a sample in a capillary tube for a melting point determination, gently tap the tube into the sample with the Choose... end of the tube down. Continue tapping until the sample Choose.. end of the tube down, tap the sample down slowly or Choose... to move the sample down Then, with the Choose... faster.
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.

Solution :

The reasons for the melting point determines  :

In order to prepare the sample in the capillary tube for determining its melting point, we tap the tube gently into the sample with the open end of tube down. We then continue tapping the tube till the sample is couple of millimeters high.

Then the other close end of tube down, we tap the sample down again slowly or then dropping the tube into a longer tube so as to move down the sample faster.

nanotechnology is a powerful tool in biomaterials research as it creates numerous possibilities for the engineering of functional molecules. nano-bio refers to projected ability to incorporate biomimicry into various materials at nanoscale.  

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e