How many atoms are in 0.75 moles of CH4?

Explanation:

Thus, if we have 6.022 × 10 23 O atoms, we say we have 1 mol of O atoms. If we have 2 mol of Na atoms, we have 2 × (6.022 × 10 23) Na atoms, or 1.2044 × 10 24 Na atoms. Similarly, if we have 0.5 mol of benzene (C 6H 6) molecules, we have 0.5 × (6.022 × 10 23) C 6H 6 molecules, or 3.011 × 10 23 C 6H 6 molecules.

For example the atomic mass of methane (CH4)is 12 amu for the carbon plus 4 x 1 amu for the four hydrogens, for a total of 16 amu. Therefore the molar mass of methane is 16g. We say that one mole of methane has a mass of 16 g, and that there are 6.022 x 1023 atoms in that mass of methane.

1. they vary with a higher number because boiling is way hotter than melting

there are two significant figures.