Answer:
1. Yes it is balanced.
2. Water in its state change. It changes the T° from 90° to 100°C. The kinetic energy of the molecules will be higher when the temperature increases.
Explanation:
1. Mg + 2HCl → MgCl₂ + H₂
The equation is balanced, just see the subscript and the stoichiometry of the reaction
You have 1 Mg in both sides, 2 Cl in both sides and 2 H in both sides.
2. Let's use water as an example.
When water changes its temperature, from 90°C to 100°C, we say that is changing from liquid state to gas.
When you give "heat" to something you are modifying its temperature. In this case, this heat increase the temperature of water. Heat is a sort of energy. For this case, the kinetic energy of molecules is higher.
If you see water on a vessel about to boil, you will see particles rising from the bottom to the surface to pass into the gaseous state. If there is an increase in the kinetic energy in the molecules, it means that they will move more freely and much more quickly, so it will be easier for them to "escape" from the liquid phase to the gas phase.
