0.72 mole of oxygen would produce 320.4 kJ of heat.
<u>Explanation:</u>
CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (ℓ) + 890kJ
According to the equation,
2 moles of O₂ produces 890 kJ of heat
So, 0.72 moles of O₂ will produce:

Therefore, 0.72 mole of oxygen would produce 320.4 kJ of heat.
U-238 has 92 protons, 146 neutrons, and 92 electrons.
Rn-222 has 86 protons, 136 neutrons, and 86 electrons.
U-238 is Uranium 238 and Rn-222 is Radon 222.
B. The nucleus of an atom contains protons and neutrons.