It comes to from the chemical reaction itself. Exothermic reaction release heat because the energy level of the products is lower than that of the reactants. Therefore, the net enthalpy change of the reaction is negative (-), meaning heat or light (or any other form of energy) is released into the environment. An example of an exothermic reaction is the combustion of fuel.
Answer:
my friend: why is there no pretty girl who swims?
me: because all of there makeup washes off in the water
Explanation:
Based on Hess's Law:
<span>2 N2(g) + 6 O2(g) + 2 H2(g) −→ 4 HNO3(l) ∆Hf = (−171.9 kJ/mol)(4 mol) </span>
<span>2 H2O(l) −→ 2 H2(g) + O2(g) ∆Hf = (-283.8 kJ/mol)(2 mol)(-1) →times -1, rxn is reversed </span>
<span>4 HNO3(l)−→ 2 N2O5(g) + 2 H2O(l) ∆Hf = (-76.4 kJ/mol)(2 mol)(-1) →times -1, rxn is reversed </span>
<span>2 N2(g) + 5 O2(g) −→ 2 N2O5(g) ∆H0 = 32.8 kJ</span>
The answer is D.
<u>Explanation</u>
Without trees, no carbon dioxide will be released into the air. It would not raise oxygen levels, and it wouldn’t effect rising sea levels.
