Quick answer: Exothermic reactions mean that heat has escaped the system. The answer is A. Heat is released.
Answer:
Manganese
Explanation:
At Mass - No neutrons = Atomic Number = #protons in nucleus
47 - 22 = 25 => At. No. 25 is Manganese (Mn)
Answer: There would have to be three nitrogen atoms in the products. The law of conservation of matter states that the amount of substance before a reaction occurs should be the same as the amount of substance after the reaction.
Explanation: This is the EXACT sample answer from the test, just reword it if you want. ^
Answer: The frequency of this light is 
Explanation:
To calculate the wavelength of light, we use the equation:

where,
= wavelength of the light =
c = speed of light = 
= frequency of light = ?

The frequency of this light is 
5. 1 hydrogen, 1 Nitrogen, 3 oxygen