posted by bryan .
Classify each of these statements as always true, sometimes true, or never true
1)___AT_____A mole of a pure substance contains 6.02 X 1023 atoms.
2)____ST____The representative particle of a compound is the molecule.
3)___NT_____A mole of CCl4 is composed of one atom of carbon and four atoms of chlorine.
4)____NT____ A mole of carbon atoms has a mass approximately three times as great as the mass of a mole of helium atoms.
1,2,3 are ok.
4 needs work.
The molar mass of He is about 4.
The molar mass of C is about 12. Look on the periodic chart to confirm this.