#7 is D because you move the decimal 4 places
the answer is 6.022×1023 atoms
Answer: 8.59 L of oxygen gas are needed to produce 100 kJ of energy at STP
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number
of particles.
Standard condition of temperature (STP) is 273 K and atmospheric pressure is 1 atmosphere respectively.
1 mole of every gas occupy volume at STP = 22.4 L
The balanced chemical reaction is:

3909.9 kJ of of energy is produced by = 
100 kJ of oxygen gas are needed to produce = 