Answer:
A Variac or Powermite; gradually; 50-60%.
Explanation:
A chemical reaction can be defined as a chemical process which typically involves the transformation or rearrangement of the atomic, ionic or molecular structure of an element through the breakdown and formation of chemical bonds to produce a new compound or substance.
Some of the laboratory apparatus (equipment) used for conducting a chemical reaction are conical flask, Bunsen burner, beaker, tongs, crucible, round bottom flask etc.
In order to heat a round bottom flask in a heating mantle, plug the heating mantle into a Variac or Powermite which is typically used for controlling the level of temperature. Turn the heat up gradually, and do not exceed 50-60% of the maximum output of the device, so as to avoid any electrical issues such as overloading, short-circuit etc.
The safety precautions that must be taken when using a round bottom flask are;
I. A proper inspection of the round bottom flask for cracks, irregularities or any imperfection.
II. Ensure you avoid heating the flask while it is closed.
III. When suspending the round bottom flask on a stand, you should ensure that you use a clamp for stability.