When calculating the enthalpy of a reaction, if the reactant has a coefficient of 2, what must be done to the δhf value of the reactant?

Explanation:

If the reactant has a coefficient of 2, it signifies that we have two moles of the reactant in that reaction. We simply multiply the  ΔHf, heat of formation of the reactant by 2 and we use it for the calculation.

n has four pairs of electrons in the valence shell, electrons repel one another ,n has 7 protons in its nucleus, and since n has 7 protons, it must fill the second shell, giving it 4 pairs of electrons. the electrons form 3 bonds and 1 lone pair of electrons. each pair of electrons repels the other pairs, so they are equally far apart.

so all of the above