What are the moles conversion formulas involving grams and formula units?

Answer 1

FORMULA UNITS TO MOLES (formula units --> moles)

Divide the number of formula units by Avogadro's number.

----------- Formula Units

Avogadro's number (formula units)

Conversion Factor

Formula Units x 1 mol

-------- Avogadro's number (formula units)

MOLES TO FORMULA UNITS (moles --> formula units)

Multiply the number of moles by Avogadro's number.

Moles Substance x Avogadro's number

Conversion Factor

Mol substance x Avogadro's number

---------------------- 1 mol substance

MOLES TO GRAMS (moles --> grams)*

Multiply the number of moles by the substance's molar mass.

Moles Substance x Molar Mass Substance

Conversion Factor

Mol Substance x Molar Mass Substance

------------------------- 1 mol Substance

GRAMS TO MOLES (grams --> moles)*

Divide the number of grams by the substance's molar mass.

---- Mass (g) Substance

Molar Mass (g) Substance

Conversion Factor

Mass (g) Substance x 1 mol substance

----------------------- Molar Mass Substance (g)

FORMULA UNITS TO GRAMS (formula units --> moles --> grams)*

Divide formula units by Avogadro's number (6.022 x 1023 formula units); multiply by molar mass.

--- Formula Units --- x --- Molar Mass

Avogadro's number

Conversion Factor

Formula Units x 1 mol ----------------- x -------------- Molar mass (g)

---------- Avogadro's number (formula units) ----------- 1 mol

GRAMS TO FORMULA UNITS (grams --> moles --> formula units)*

Divide mass of substance by the molar mass of substance; multiply by Avogadro's number.

---- Mass (g) substance -- x -- 6.022 x 1023 molecules

Molar mass (g) substance

Conversion Factor

--- Mass substance (g) x 1 mol substance ------ x ----- Avogadro's number

------------------------ Molar Mass (g) substance ----------- 1 mol substance

Tip: On test day, anytime you see the words ions, formula units, molecules, or atoms on a question, that problem will involve the usage of Avogadro's number.

*Finding Molar Mass

# Atoms Element A x Atomic Mass Element A (Periodic Table) = mass (g) El. A

# Atoms Element B x Atomic Mass Element B (Periodic Table) = mass (g) El. B

... etc.

Add up all the mass values found above and you have molar mass.