2Describe the concept of the mole and its importance to measurement in chemistry. Calculate the mass of compounds in atomic mass units.Calculate the molar mass of various substances.Additional KEY TermsAvogadro’s number
3Particles are now counted in moles (n). Avogadro ( )Any sample of any gas at the same temperature and pressure will contain the same number of particles.Defined 22.4 L as the molar volume for any gas.Particles are now counted in moles (n).
4The mass of 1 mole is the molar mass - (g/mol) One mole of any particle has a mass equal to its total formula mass – IN GRAMS.The mass of 1 atom of Al = 27.0 µThe mass of 1 mole of Al atoms = 27.0 gThe molecular mass of water (H2O) is 18.0 µ ...So...the molar mass of water is 18.0 g/mol.
5What is the molar mass of ammonium dichromate? (NH4)2Cr2O7Determine the molar mass.1 mole of (NH4)2Cr2O7 = 2 N + 8 H + 2 Cr + 7 O= 2(14.0g/mol)+ 8(1.0g/mol)+ 2(52.0g/mol)+ 7(16.0g/mol)(NH4)2Cr2O7 = g/mol
7Rules for using a Dimensional Analysis 1. Start with what you know2. Put ratio units you want to cancel on bottom3. Put ratio units you need on the top4. Multiply across the top, Divide across the bottomHow many pizzas would 250 pieces of pepperoni make?250 pepperoni1 slice1 pizza= 7.8 Pizzas4 pepperoni8 slice
8154.0 g 1 mole 154.0 g 1 mole or 1.20 x 10-5 mol 1 mol 154.0 g What is the mass of 1.20 x 10–5 moles of carbon tetrachloride, CCl4?CCl4 = 1 C + 4 Cl= 1(12.0 g/mol) + 4(35.5 g/mol)= g/mol154.0 g1 mole154.0 g1 moleor1.20 x 10-5 mol1 mol154.0 g1.85 x 10-3 g
10In one mole there is 6.02 x 1023 particles. We call this - Avogadro's Number6.02 x particles1 moleThe term "particle" refers to any individual thing like atoms, formula units, molecules, ions, etc.6.02 x particles1 moleor6.02 x pencils is 1 mole of pencils6.02 x carbon atoms is 1 mole…6.02 x water molecules is 1 mole…
11= = 1 mole 1 mole How many atoms in 25.0 moles of copper? 25.0 mol Cu6.02 x particles=1.51 x atoms1 moleHow many molecules of water in 1.50 x 10–5 moles?6.02 x particles1.50 x 10–5 mol H2O=9.03 x 10 18molecules of water1 mole
12= How many moles is 5 atoms of zinc? 1 mole 8.31 x 10-24 moles 5 atoms Zn1 mole=8.31 x moles6.02 x particles5 atoms of Zinc is 8.31 x 10–24 moles.
13The mole allows the conversion between mass and number of particles.
14= = 0.556 mol H20 3.34 x 10 23 molecules H20 1 mole 1 mole 18.0 g How many molecules of water in a 10.0 g sample of water?10.0 g H2O1 mole=0.556 mol H2018.0 g0.556 mol H2O6.02 x particles1 mole=3.34 x molecules H20
15Put the two equations together 10.0 g H2O1 mole6.02 x particles of H2O18.0 g1 mole=3.34 x molecules H20There are 3.34 x 1023 molecules in 10.0 g of water.
16= 5.14 x 10 23 atoms 1 mole 2 atoms 1 For. U How many atoms in 25.0 g of sodium chloride?NaCl = 58.5 g/mol1 mole6.02 x For.U25.0 g NaCl58.5 g2 atoms1 For. U=5.14 x atoms
17CAN YOU / HAVE YOU?Describe the concept of the mole and its importance to measurement in chemistry.Calculate the mass of compounds in atomic mass units.Calculate the molar mass of various substances.Additional KEY TermsAvogadro’s number