Question

In when converting atoms into moles or moles into mass each time the exponent changes it is either negative or positivewhy does the exponent change i get everything else about the conversions but that specific part.

Answer 1

Answer on Question #74098 – Chemistry – General Chemistry

In when converting atoms into moles or moles into mass each time the exponent changes it is either negative or positive. Why does the exponent change, i get everything else about the conversions but that specific part.

Solution:

Converting from particles (atoms, molecules, or formula units) to moles: Divide your particle value by Avogadro’s number, $6.02 \times 10^{23}$. Moles are always positive.

Example:

$$\mathrm{N}(\mathrm{CO}_2) = 12.04 \times 10^{23}$$ $$\mathrm{n}(\mathrm{CO}_2) = \mathrm{N}(\mathrm{CO}_2) / \mathrm{N}_\mathrm{A} = 12.04 \times 10^{23} / 6.02 \times 10^{23} = 2 \mathrm{~mol}$$

Converting from moles to mass (grams): Multiply your initial mole value by the molar mass of the compound as determined by the periodic table. Mass has always positive values.

Example:

$$\mathrm{n}(\mathrm{CO}_2) = 2 \mathrm{~mol}$$ $$\mathrm{m}(\mathrm{CO}_2) = \mathrm{M}(\mathrm{CO}_2) \times \mathrm{n}(\mathrm{CO}_2) = 44 \mathrm{~g/mol} \times 2 \mathrm{~mol} = 88 \mathrm{~g}$$