# Review Molar Mass of Compounds l Ex Molar

• Slides: 16

Review: Molar Mass of Compounds l Ex. Molar mass of Ca. Cl 2 20 Avg. Atomic mass of Calcium = 40. 08 g l Avg. Atomic mass of Chlorine = 35. 45 g l l Ca 40. 08 17 Cl 35. 45 Molar Mass of calcium chloride = 40. 08 + 35. 45(2) = _110. 98______ g/mol Ca. Cl 2

Practice l Calculate the Molar Mass of calcium phosphate Formula = l Ca 3(PO 4)2 Masses elements: Ca = 40. 08 g/mole P = 30. 97 g/mole O = 16. 00 g/mole l Molar Mass = l (40. 08 g/mole)(3) + (30. 97 g/mole)(2) + (16 g/mole)(8) = 310. 18 g/mole

Mole Conversions Learning Target: Understand how molar mass relates to the number of moles and particles of a substance.

Particles (atoms, Formula units, molecules) Divide by 6. 02 X 1023 Multiply by 6. 02 X 1023 Moles Multiply by molar mass from periodic table Divide by molar mass from periodic table Mass (grams)

l 3. 5 dozen roses = ? ? Roses l 2. 5 mol roses = ? ? Roses (use Avogadro's #)

Problem Type #1 – Moles to Mass l Find the mass of 0. 760 mol of magnesium bromide. . l Find the molar mass of the compound: l Make the conversion:

Problem Type # 2– Mass to Moles l A bottle of copper (II) nitrate contains 110. 6 g of compound. How many moles of copper (II) nitrate are in the bottle?

Problem Type #3 – Moles to Particles l Determine the number of atoms that are in 0. 78 mol of mercury.

Problem Type #4 – Particles to Moles l How many moles of zinc sulfate contain 5. 40 x 1024 formula units?

Multi-step Mole Conversions l 2. 5 g Roses = ? ? atoms of roses l Atomic mass of 1 Rose is 3. 0 g/mol

Multi-step Practice l How many molecules are in 7. 4 g of potassium phosphate?

Multi-step Practice l How many grams of sodium bicarbonate are in 1. 8 x 1023 formula units?

Molar Volume l Definition: The volume of one mole of an ideal gas at standard conditions (STP) equal to 22. 4 L. l STP = standard temperature and pressure which is 0ºC and 1 atmospheric pressure (760 mm. Hg) l 1 mole gas at STP = 22. 4 L

Particles (atoms, Formula units, molecules) Divide by 6. 02 X 1023 Multiply by 6. 02 X 1023 Moles Multiply by 22. 4 L Divide by 22. 4 L Volume (L)

Practice l A container with a volume of 563 L contains how many moles of air at STP? l How many molecules of air?

Practice l A chemical reaction produced 0. 78 mol of H 2 gas. What volume will the gas occupy at STP? l How many molecules of H 2? l How many atoms of hydrogen?