Answer:
In chemistry the reactivity series is an empirical, calculated, and structurally analytical progression of a series of metals, arranged by their "reactivity" from highest to the lowest.
15. D is correct, exothermic reactions release heat
I am not sure about 16
Answer:

Explanation:
You must calculate the moles of P₄O₁₀, convert to moles of P₂O₅, then convert to molecules of P₂O₅.
1. Moles of P₄O₁₀

2. Moles of P₂O₅
P₄O₁₀ ⟶ 2P₂O₅
The molar ratio is 2 mol P₂O₅:1 mol P₄O₁₀
3. Molecules of P₂O₅
