 # 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.

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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.  Solve problems requiring conversions between mass, and number of particles, and moles.

We call this - Avogadro's Number In one mole there is 6.02 x 10 23 particles. One mole contains 6.02 x 10 23 of anything 6.02 x 10 23 pencils is 1 mole of pencils 6.02 x 10 23 carbon atoms is 1 mole… 6.02 x 10 23 water molecules is 1 mole…

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

Molar mass of lead (II) chloride, PbCl 2 ? 1 particle of PbCl 2 - 1 atom of Pb, 2 atoms of Cl 1 mole of PbCl 2 - 1 mole of Pb, 2 moles of Cl PbCl 2 = 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.

What is the molar mass of ammonium dichromate? Determine the molar mass. 1 mole of (NH 4 ) 2 Cr 2 O 7 = 2 N + 8 H + 2 Cr + 7 O = 2(14.0 g/mol )+ 8(1.0 g/mol )+ 2(52.0 g/mol )+ 7(16.0 g/mol ) (NH 4 ) 2 Cr 2 O 7 = 252.0 g/mol (NH 4 ) 2 Cr 2 O 7

Calculating Moles And the Factor Label Line

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

What is the mass of 1.20 x 10 –5 moles of carbon tetrachloride, CCl 4 ? CCl 4 =1 C + 4 Cl = 1(12.0 g/mol) + 4(35.5 g/mol) =154.0 g/mol or 154.0 g 1 mole 1.20 x 10 -5 mol 1 mol 154.0 g 1 mole 1.85 x 10 -3 g

1. 5.00 moles of aluminum atoms. 2. 100.0 g of sugar, C 11 H 22 O 11 3. 7.25 moles of iron (III) oxide. 4. 1.42 x 10 -3 g of copper (II) sulphate. 1.Al = 27.0 g/mol= 135 g 2.C 11 H 22 O 11 = 330.2 g/mol= 0.303 mol 3.Fe 2 O 3 = 159.6 g/mol=1160 g 4.CuSO 4 = 159.6 g/mol= 8.90 x 10 -6 mol

Calculating the Number of Particles

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

How many atoms in 25.0 moles of copper? 25.0 mol Cu 1.51 x 10 25 atoms = How many molecules of water in 1.50 x 10 –5 moles? = 9.03 x 10 18 molecules of water 1.50 x 10 –5 mol H 2 O 6.02 x 10 23 particles 1 mole 6.02 x 10 23 particles 1 mole

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

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

How many molecules of water in a 10.0 g sample of water? 0.556 mol H 2 0 = 1 mole 18.0 g 10.0 g H 2 O 0.556 mol H 2 O 6.02 x 10 23 particles 1 mole = 3.34 x 10 23 molecules H 2 0

we can put the two equations together There are 3.34 x 10 23 molecules in 10.0 g of water. 1 mole 6.02 x 10 23 particles of H 2 O 10.0 g H 2 O 18.0 g 1 mole = 3.34 x 10 23 molecules H 2 0

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

 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 10 23 particles - Avogadro’s Number.  Using molar mass, we can move between moles, mass, particles of a given substance.

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