Question

Hydrogen peroxide will decompose if the bottle is left open, and the resulting release of energy will heat up the solution. Which of the following best describes this type of reaction?

1. endothermic
2. exothermic
3. combustion
4. synthesis

Answer 1

Answer is: 2. exothermic.

There are two types of reaction:

1) exothermic reaction (chemical reaction that releases more energy than it absorbs).

For example, ΔH(reaction) = -225 kJ/mol; this is exothermic reaction.

2) endothermic reaction (chemical reaction that absorbs more energy than it releases).

Hydrogen peroxide (H₂O₂):

1) have molecular structure.

2) it is higly reactive, it is not physically and chemically stable.

3) has low boiling point (around 150°C), because weak covalent bonds.

4) dissolve in water, because it has polar bond.