Molecules in a Flask: Understanding Heating and Cooling Process

Does the flask contain more, fewer, or the same number of molecules after heating? Explain why.

Choose the correct answer:

A. More molecules

B. Fewer molecules

C. The same number of molecules

Answer:

The correct answer is B. Fewer molecules.

When an open flask is heated, it will contain fewer molecules after it is stoppered and allowed to cool.

Explanation: When an open flask is heated, the heat energy causes the molecules in the flask to move more rapidly. As a result, more molecules escape from the liquid and enter the gaseous phase. When the flask is stoppered and allowed to cool, some of the gas will condense back into a liquid, but not all of it. Therefore, the flask will contain fewer molecules after heating and cooling compared to before.

It is important to understand the process of heating and cooling in a flask to comprehend the changes in the number of molecules present. This knowledge can be useful in various scientific experiments and understanding of thermodynamics.