Name: ______Date: ______Period: ______

Moles, Moles and More Moles – Unit 9 Quiz Review

Comparing atomic mass to molar mass

  • The molar mass is the mass of ______atoms.
  • Numerically the atomic mass and the molar mass are [the same, different] (circle one)
  • For example the atomic mass of sodium is ______AND the molar mass of sodium is ______.
  • Both numbers come from the ______.
  • Quantitatively the atomic mass and the molar mass are[the same, different] (circle one)
  • For example the atomic mass is the mass of ______atom and has units of ______.
  • The molar mass is the mass of ______atoms and has units of ______.

Molar Mass Practice Problems – REMEMBER this is addition…sig figs are to place value!!!

Determine the molar mass of the following using your periodic table. Remember, the units are g/mol.

1. Li2. Ca3. Al4. Cl25. O2

6. KCl7. MgI28. CCl49. Al2O310. SiO2

11. H212. CO213. Na2CO314. H2O15. NH3

16. Cu17. Ne18. Phosphorus19. C6H12O6

Chemical Quantities - CONVERTING BETWEEN MASS, MOLES AND PARTICLES

  • When converting from grams to moles OR from moles to grams you use the ______of the element or compound. You can tell because the conversion factor has units of ______.
  • When converting from moles to molecules OR molecules to moles you use ______’s number which is equal to ______. You can tell because the conversion factor has units of ______.
  • When converting from atoms to moleculesORmolecules to atoms you use the chemical formula which tells how many ______are in one molecule.

SHOW ALL WORK AND INCLUDE ALL LABELS FOR THESE TYPES OF PROBLEMS

20. Calculate the # of atoms in 25g Ni -

  1. How many moles is 4.54 x 1022 molecules of H2O?
  1. How many grams are in 2.8 mol of H2?
  1. How many molecules of NH3 are in 5.0 moles of NH3?
  1. What is the number of moles in 125g of sodium carbonate (Na2CO3)?
  1. How many moles of copper is 127.1 g of copper?
  1. How many atoms of phosphorous are there in 90.0 g of phosphorous?
  1. What is the mass of 1.74 x 1024 Ne atoms?
  1. How many atoms are there is 36g glucose ( C6H12O6)?
  1. How many O atoms are in 12g of CO2?

% Composition & Empirical Formulas

Show all work, units, and round correctly.

  1. Determine the empirical formula for a compound containing: 63.50% Ag, 8.25% N, and 28.25% O.
  1. Determine the percent composition of each element in a chemical sample that contains: 21.49 g Na, 56.15 g C, 9.43 g H, 74.81 g O, and 13.11 g N.
  1. Determine the empirical formula for the compound in the previous question.