Chapter U4.2, Problem 2E

Interpretation Introduction

Interpretation:

Chemical equations must be used to describe the difference between sugar melting and sugar decomposing.

Concept introduction:

Melting is a physical change in which solid is converted to liquid. Decomposing is a chemical change in which one or more than one new substances are generated from a substance.

Answer to Problem 2E

  $\begin{array}{l}{C}_{12}{H}_{22}{O}_{11}\left(s\right)+heat\to C_{12}{H}_{22}{O}_{11}\left(l\right)\hfill \\ \hfill \\ C_{12}{H}_{22}{O}_{11}\left(s\right)\to C_6{H}_{12}{O}_6\left(Glucose\right)+C_6{H}_{12}{O}_6\left(Fructose\right)\hfill \\ \hfill \\ C_{12}{H}_{22}{O}_{11}\left(s\right)+heat\to 12C+11H_{2}O\hfill \end{array}$

Explanation of Solution

In sugar melting, the intermolecular force is decreased due to providing thermal energy. This results in the incerase in the intermolecular distance. Thus, solid sugar is converted to liquid sugar.

In sugar decomposing, the disaccharide is converted to two monosaccharides which are glucose and fructose. This is chemical change as new substances are generated.

Sugar can also decompose to generate solid carbon after removal of water.