Answer:
A
Explanation:
A) The molecular mass of a compound is the atomic mass of this compound but in grams, we know that the magnesium has an atomic mass of 24 u and the carbon has and atomic mass of 12 u, so the molecular mass of magnesium is 24g and the molecular mass of carbon is 12g, so a mole of magnesium has a greater mass.
B) A mole of any given substance is the avogadro number, 6.023 10^23 molecules, so a mole of magnesium and a mole of carbon has the same amount of atoms.
C) The molecular mass of a compound is the atomic mass of this compound but in grams, we know that the magnesium has an atomic mass of 24 u and the carbon has and atomic mass of 12 u, so the molecular mass of magnesium is 24g and the molecular mass of carbon is 12g, so a mole of magnesium has a greater mass.
D) The molecular mass of a compound is the atomic mass of this compound but in grams, we know that the magnesium has an atomic mass of 24 u and the carbon has and atomic mass of 12 u, so the molecular mass of magnesium is 24g and the molecular mass of carbon is 12g, so a mole of magnesium has a greater mass.