How much heat is given off when 8 g of hydrogen reacts in: 2h₂ + o₂ → 2h₂o; δh = -115.60 kcal
a. -57.8 kcal
b. -115.6 kcal
c. -173.4 kcal
d. -231.2 kcal
e. -462.4 kcal

ΔΗ= -115.6 kJ/mol
H2 has a Mr of 2, so as mol=mass/mr we can work out that there are 4 moles of H reacting

Therefore we multiply -115.6 by 4 = -462.4

The correct answer is d

Because electrons have negligible mass, to account for the mass of the isotope, there must be 16 neutrons, 16 neutrally charged, massive, fundamental particles present in the sulfur nucleus. and thus finally, if we have the 32s2− ion, there are 18 electrons, 16 protons, and 16 neutrons.