Mass, if you know what element you are working with.
<span>C + O2 → CO2
(8,376,726 tons) x (0.80) / (12.01078 g C/mol) x (1 mol CO2/ 1 mol C) x
(44.00964 g CO2/mol) = 24,555,054 tons CO2</span>
The bond angle in the Water Molecule is approx. 104.5 degrees. The methane molecule is approx. 109.5 degrees. The differences, is due to the force from the surrounding molecules and atoms. For example the Lone pairs of electrons.
We are given with the mass of Arsine (
The mass of arsine is 15g
there is a relation between moles, mass and molar mass of any compound which is

The molar mass of Arsine = atomic mass of As + 3X atomic mass of H
the molar mass of Arsine = 74.92 + 3X 1 = 77.92 g/mol
Let us calculate the moles as

The answer would be D. The only minerals harder than corundum is diamond.