Mole Unit Packet Please understand that you will NOT receive another copy of this packet! Name: Period:
Introduction to The unit of the Mole is the HEART of all chemistry and most of its calculations. the Mole molecules grams MOLE atoms But remember all the mole is - is a UNIT! It is used for counting.
Mole Conversions 1 mole = 6.02 10 23 anythings 1 mole OR 6.02 10 23 6.02 10 23 1 mole So when solving problems involving a number of particles, be it atoms, ions or molecules - use the following format: ### answer unit Given Information with unit x = Answer with unit ### given unit Ex. 1 Calculate the number of moles in 3.45 10 22 molecules of oxygen. 1 mole = molar mass of a substance 1 mole OR molar mass molar mass 1 mole So when solving problems involving a number of particles, be it atoms, ions or molecules - use the following format: ### answer unit Given Information with unit x = Answer with unit ### given unit Ex. 1 Calculate the mass of 1.21 moles of iron.
Molar/Formula Mass Definition: units: Example Copper (II) Chloride ( CuCl2 ) name of component number of each atomic mass of mass of atoms atom component atom atom in compound Copper 1 63.55 63.55 Chlorine 2 35.45 70.90 molar mass of copper (II) chloride = 134.45 g/mol Sucrose ( C12H22O11 ) name of component number of each atomic mass of mass of atoms atom component atom atom in compound molar mass of sucrose = Barium chlorate ( Ba(ClO3) 2 ) name of component number of each atomic mass of mass of atoms atom component atom atom in compound molar mass of sucrose =
Mass Percent/Percent Composition Definition: Equation used to determine the Mass Percent of a compound: Mass Percent = X 100 How is mass percent calculated? 1. Determine the of the compound. 2. the of each element by the of the compound. Examples: C3H8: C = 3 x 12.01 = 36.03 H = 8 x 1.01 = 8.08 44.11 g/mol C = H = 36.03 / 44.11 = 81.68 % C 8.08 / 44.11 = 18.32 % C Examples #2:
Empirical Formulas Definition: ex: true formula factor empirical formula But how do we figure this out? Steps for Solving Empirical Formula Problems: 1. Determine the of each element in the formula. a. If percentages are given - simply. b. If masses are given - to determine the one not given. 2. Determine the of each element in the formula. (by of the mass of the element) 3. Determine the of elements in the compound, by the smallest. Write the formula. Example #1 Example #2
Molecular Formulas Definition: ex: empirical formula multiple molecular formula But how do we determine the multiple? Steps for Solving Molecular Formula Problems: a. If you do not have an empirical formula you must determine it for yourself. 1. Determine the of the empirical formula. 2. the of the compound by the of the empirical formula. 3. Multiply the by the empirical formula and write the new formula. Example #1
Molecular Formulas Problems 1. A compound with an empirical formula of CH3 has a molar mass of 30.1 g/mole. Determine the molecular formula for this compound. 2. A compound with an empirical formula of N2O has a molar mass of 34.0 g/mole. What is its molecular formula? 3. Determine the molecular formula of a compound that has a molar mass of 180 g/mole and an empirical formula of CH2O. 4. A 7.00-g sample of a molecular compound whose molar mass is 32.00 g/mol is analyzed and is found to yield 6.13 g of nitrogen and 0.87 g of hydrogen. Determine the empirical and molecular formulas of the compound. 5. Butane is a liquid hydrocarbon made up of carbon and hydrogen only. A 348 g sample of the compound is tested and it produced 288 g of carbon. If the molecular formula has a molar mass of 58.1 g/mole, what are the empirical and molecular formulas for this compound?
Empirical Formula Problems 1. A compound containing only silicon and oxygen has a mass of 120 g. The silicon in that compound has a mass of 56.2 g. What is the empirical formula for this compound? 2. Scientist have analyzed a compound, with a mass of 22.4 g, and found it to contain 14.0 g of iron, 0.50 g of hydrogen and the rest oxygen. What is the empirical formula for this compound? 3. A 510 g sample of aluminum oxide produced 240 g of oxygen when it was heated. Determine the empirical formula for this compound. 4. A compound was determined to contain 6.355 g of copper, 4.80 gams of carbon, 0.606 grams of hydrogen and 6.40 grams of oxygen. What is the empirical formula for the compound? 5. A compound was analyzed and found to contain 49.5 % carbon, 5.15 % hydrogen, 28.87 % nitrogen and the rest was oxygen. What is the empirical formula for this addictive drug?
Empirical Formula Lab
1. CaCO3 Mass Percent Problems Ca = C = O = 2. KCl K = Cl = 3. BaBrO3 Ba = Br = O = 4. (NH4)2SO4 N = H = S = O = 5. CuSO4 5 H2O Cu = S = O = H2O =
Mass Percent Lab Instructions: All data must be recorded on the front of this card during the lab. All calculations should be completed on the back in an orderly manner. Procedure: 1. Make three notches in the edges of a clean penny to expose the zinc below the surface. 2. Measure and record the mass of the penny. 3. Place the penny in a beaker with 20 ml of 6M HCl. 4. Allow the penny to react for 24 hours. 5. Complete the problems on the back of this card. 6. After 24 hours - rinse and dry the penny. Record the mass. 7. Calculate the percent of copper in the penny. Data: mass of penny ( before ) mass of penny ( after ) Percent of Copper Problems > Determine the mass percent of each of the following compounds. 1. KMnO4 2. HCl 3. Mg(NO3)2 4. (NH4)3PO4 5. Al2(SO4)3 6. C8H18
Formula Mass Problems Calculate the molar mass of each of the following compounds. methane CH4 morphine C15H12O3N oxygen gas O2 benzene C6H6 ozone O3 propane C3H8 aspirin C9H8O4 Freon-113 C2Cl3F3 trinitrotoluene C7H5(NO2)3 sodium chloride NaCl ammonium phosphate (NH4)3PO4 copper ( I ) sulfide Cu2S Show work here!
Mole Conversion Problems How many atoms are in the quantities below? 1. 2.0 moles 2. 1.5 moles How many moles are in the number of molecules below? 3. 6.02 X 10 23 4. 1.5 X 10 20 How many moles are in the number of grams below? 5. 32.0 grams of chlorine 6. 1500 grams of radium How many grams are in the number of moles below? 7. 0.35 moles of sulfur 8. 1.05 moles of barium Perform the following conversions. 9. Calculate the number of atoms in 13.0 grams of aluminum. 10. Calculate the mass of 1.5 X 10 20 atoms of iodine.