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Chemical Quantities

Chemical Quantities. Calculate the mass of compounds. Calculate the volume of a given mass of a gas from its density at a given temperature and pressure. Calculate the molar volumes of gases from their densities at a given temperature and pressure and compare the calculated volumes.

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Chemical Quantities

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  1. Chemical Quantities

  2. Calculate the mass of compounds. • Calculate the volume of a given mass of a gas from its density at a given temperature and pressure. • Calculate the molar volumes of gases from their densities at a given temperature and pressure and compare the calculated volumes. • Solve problems requiring conversions between mass, and number of particles, and moles.

  3. In one mole there is 6.02 x 1023particles. We call this - Avogadro's Number One mole contains 6.02 x 1023 of anything 6.02 x 1023 pencils is 1 mole of pencils 6.02 x 1023 carbon atoms is 1 mole… 6.02 x 1023 water molecules is 1 mole…

  4. The mass of one mole is called the molar mass - units are grams per mole (g/mol) One mole of any particle has a mass equal to its total atomic/formula/molecularmass – IN GRAMS (g). One mole of aluminum atoms has a mass of 27.0 g. The molecular mass of water is 18.0 µ ... So...the molar mass of water is 18.0 g/mol.

  5. Molar mass of lead (II) chloride, PbCl2 ? 1 particle of PbCl2 - 1 atom of Pb, 2 atoms of Cl 1 mole of PbCl2 - 1 mole of Pb, 2 moles of Cl PbCl2 = 207.2 g/mol + 2(35.5 g/mol) = 278.2 g/mol The molar mass of lead (II) chloride is 278.2 g/mol.

  6. What is the molar mass of ammonium dichromate? (NH4)2Cr2O7 Determine 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 = 252.0 g/mol

  7. Calculating Moles And the Factor Label Line

  8. The Factor Label line is used to organize calculations, ratios, and to choose the right units for the answer. Rules for using a Factor Label Line 1. Start with what you know 2. Put the unit you want to get rid of on the bottom 3. Put the unit you want on the top 4. Multiply across the top, Divide across the bottom

  9. 1 mole 154.0 g 1 mole 154.0 g 154.0 g 1 mol 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) = 154.0 g/mol or 1.20 x 10-5 mol 1.85 x 10-3 g

  10. 1. 5.00 moles of aluminum atoms. 2. 100.0 g of sugar, C11H22O11 3. 7.25 moles of iron (III) oxide. 4. 1.42 x 10-3 g of copper (II) sulphate. • Al = 27.0 g/mol = 135 g • C11H22O11 = 330.2 g/mol = 0.303 mol • Fe2O3 = 159.6 g/mol =1160 g • CuSO4 = 159.6 g/mol = 8.90 x 10-6 mol

  11. Calculating the Number of Particles

  12. One mole of anything contains 6.02×1023 individual particles. The term "particles" refers to any individual thing like atoms, formula units, molecules, ions, etc. 1 mole 6.02 x 10 23 particles or 1 mole 6.02 x 10 23 particles

  13. How many atoms in 25.0 moles of copper? 6.02 x 10 23particles 25.0 mol Cu = 1.51 x 10 25 atoms 1 mole How many molecules of water in 1.50 x 10–5 moles? 6.02 x 10 23particles 1.50 x 10–5 mol H2O 9.03 x 10 18 molecules of water = 1 mole

  14. How many moles is 5 atoms of zinc? 1 mole 5 atoms Zn = 8.31 x 10-24 moles 6.02 x 10 23particles 5 atoms of Zinc is 8.31 x 10–24 moles.

  15. The mole allows the conversion between mass and number of particles.

  16. How many molecules of water in a 10.0 g sample of water? 10.0 g H2O 1 mole = 0.556 mol H20 18.0 g 0.556 mol H2O 6.02 x 10 23particles 1 mole = 3.34 x 10 23 molecules H20

  17. we can put the two equations together 10.0 g H2O 1 mole 6.02 x 10 23particles of H2O 1 mole 18.0 g = 3.34 x 10 23 molecules H20 There are 3.34 x 1023 molecules in 10.0 g of water.

  18. 2 atoms 25.0 g NaCl 1 mole 6.02 x 10 23For.U 1 mole 1 For. U 58.5 g How many atoms in 25.0 g of sodium chloride? NaCl = 58.5 g/mol = 5.14 x 10 23 atoms

  19. The formula mass, in amu, is the sum of the atomic masses of all atoms in one substance. • The molar mass of a substance is the mass of one mole of that substance, or its formula mass in grams. • The mole is equal to 6.02 x 1023 particles - Avogadro’s Number. • Using molar mass, we can move between moles, mass, particles of a given substance.

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