A sugar cube in a test tube is heated over a Bunsen burner. The sugar cube turns black and has

less mass than before it was heated. These changes occur because the sugar has-

A. become hydrated

B. reacted chemically

C. melted

D. boiled

The correct answer is B reacted chemically.

Explanation:

When a sugar cube in a test tube is heated over a bunsen burner the sugar cube turns back because the heat that is generated by the Bunsen burner dehydrate the sugar molecule.

As a result the sugar molecule lost water from its chemical structure which causes the sugar molecule to turn black. As water molecules are lost from the sugar the mass of the sugar molecule is being decreased from its original or primary mass.

In general the sugar molecule undergo dehydration reaction which is responsible for the black coloration of the sugar as well asw los of mass from the sugar molecule.