Chemistry Mole-Mass-Particles: Key Formulas and Practice Examples

What is a mole in chemistry?

A counting unit equal to 6.022 × 10^23 particles (atoms, molecules, ions, etc.)

What is Avogadro's number?

6.022 × 10^23 — the number of particles in one mole.

How do you convert grams to moles?

mol = grams / molar mass

How do you convert moles to particles?

particles = mol × 6.022 × 10^23

How do you convert moles to volume in a solution?

volume (L) = mol / molarity

How do you find mass from volume and density?

mass = volume × density

How do you convert molecules to grams?

Step 1: mol = molecules / 6.022 × 10^23; Step 2: grams = mol × molar mass

Convert 36.0 g of H₂O to moles.

mol = 36.0 / 18.02 ≈ 2.00 mol

Convert 4.50 mol of Na to atoms.

atoms = 4.50 × 6.022 × 10^23 = 2.71 × 10^24

How many liters of 2.00 M acetic acid are needed for 5.25 mol?

volume = 5.25 / 2.00 = 2.625 L

How many moles are in 150.0 mL of ethanol (density = 0.789 g/mL)?

Step 1: mass = 150.0 × 0.789 = 118.35 g; Step 2: mol = 118.35 / 46.07 ≈ 2.57 mol

How many molecules are in 56 g of N₂?

Step 1: mol = 56 / 28.02 = 2.00 mol; Step 2: molecules = 2.00 × 6.022 × 10^23 = 1.20 × 10^24

How many grams of NH₃ are in 2.70 × 10^24 molecules?

Step 1: mol = 2.70 × 10^24 / 6.022 × 10^23 = 4.48 mol; Step 2: grams = 4.48 × 17.03 = 76.3 g