Chapter 3, Problem 41A

Interpretation Introduction

Interpretation:

The unknown compound based on its physical properties.

Concept introduction:

A physical property describes the physical changes of a substance. Physical change is a temporary change; it is a reversible change. For example, color, mass, volume, etc. Physical properties (such as boiling point, density) are fixed for any substances.

Answer to Problem 41A

Sucrose decomposes before its boiling point. So, the unknown compound is sucrose.

Explanation of Solution

The known table is:

Physical properties of Common Substances
Substance	Color	State at $2\text{5°C}$	Boiling point ( ${}^{\text{°}}\text{C}$ )
Oxygen	Colorless	Gas	$-183$
Water	Colorless	Liquid	$100$
Sucrose	White	Solid	Decompose
Sodium chloride	White	Solid	$1413$

The temp at which vapor pressure of a liquid equals (similar in quantity) the external pressure or atmospheric pressure is defined as boiling point.

From the given table, only two compounds that are solid and white. Also, the table shows that sucrose decomposes before a boiling point. So, the unknown compound is sucrose.

Conclusion

The unknown compound is sucrose.