Answer:
Example that involves phase change in which heat energy is released by substance:
Explanation:
If heat is removed from a substance, such as in freezing and condensation, then the process is exothermic. In this instance, heat is decreasing the speed of the molecules causing them move slower (examples: liquid to solid; gas to liquid). These changes release heat to the surroundings.3 days ago
Solid → Liquid: Melting or fusion
Gas → Liquid: Condensation
Liquid → Gas: Vaporization
Liquid → Solid: Freezing
Answer:

Explanation:
Empirical formula of ionic compound formed by two ions
and
is
(for
) of AB (for x = y)
The above empirical formula is in accordance with charge neutrality principle
Here each cation (
and
) can form two ionic compounds by combining with two given anions (
and
).
So the four ionic compounds are: 
Answer: (D) environmental chemistry
Explanation: