1 Answers

In an experiment in which molten naphtha-lene is allowed to cool…

Posted by: 653 views ,
PHYSICS

In an experiment in which molten naphtha-lene is allowed to cool

In an experiment in which molten naphtha-lene is allowed to cool, the cooling curve in figure 7 was obtained. The temperature 80°C is known as the

A. cooling temperature

B. boiling point

C. melting point

D. vaporization point

QUICK ANSWER…

C

DETAILS…  

As temperature increases from right to left, the first step is the melting point, and the second step is the boiling point.

Firstly, as heat is applied to the naphthalene, it melts at 80°c. As the heat continues, it then boils at 90°c (according to the graph at least).

Now for the right answer to the above question:

  1. A is not the right answer. all the temperatures can be regarded as cooling temperatures if they are reducing.
  2. B is incorrect. the boiling point will be the point where the naphthalene changes from liquid to gas or from gas to liquid. It is the second step on the left hand side.
  3. C is correct.
  4. D is incorrect. not vaporization point.

KEY-POINTS…

You may please note this/these:

  • As temperature increases from right to left, the first step is the melting point.
  • And the second step is the boiling point.

You are free to add your own answers below this page to assist others improve their learning.

You can also click the golden ASK A QUESTION BOTTON down this page to raise new related questions… OUR COMMUNITY OF EXPERTS WILL BE MORE THAN HAPPY TO TACKLE IT…

/ culled from 2020 JAMB-UTME physics past question 35 /

Answer Question