If they weren't limited then it would make other elements rather than the element itself.
A pure substance is not mixed with any other substances. Therefore it is a lonely substance :(
Answer:
Oxygen is an element.
Explanation:
Out of the choices listed, oxygen is the only element. The other choices are incorrect because air is a mixture of nitrogen, oxygen, carbon dioxide, water vapors, and some other gases; water is a compound of hydrogen and oxygen; and sodium chloride is a compound of sodium and chloride ions; meanwhile, oxygen is a pure element.
I believe that the choices for this question are:
C2H4O2, C4H8O4 <span>
CH2O, C6H12O6
C3H6O3, C6H12O6
C2H4O2, C6H12O6 </span>
The answer to this based on the molar masses given is:
C2H4O2, C6H12O6
To prove calculate the molar mass:
C2H4O2 = 2*12 + 4*1 + 2*16 = 60
C6H12O6 = 6*12 + 12*1 + 6*16 = 180
5.0x10^1 kg is the correct answer
