I believe the correct answer would be the standard heat of formation. The keyword in the statement would be synthesis and standard state. Synthesis would always mean formation of something and standard states would mean at a temperature of 25 C and 1 atm pressure.
The compound Fe2O3 contains C) 5 total atoms.
This is because there are 2 atoms of Fe (iron) and 3 atoms of O (oxygen) bonded together in this compound, as denoted by the subscripts, and 2+3 = 5.
Hope this helps!
Gravity pulls gas and dust together. A protostar forms as mass increases.
