counting atoms chapter 9. mole?? moles of particles in one mole of a substance, there are 6 x 10 23...
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Counting AtomsChapter 9
MOLE??
Moles of Particles
In one mole of a substance, there are 6 x 1023 particles
Calculating the number of moles from the number of particles
TB P147
1. Calculate the number of moles of particles in a. 2.4 x 1023 atoms of hydrogen, Hb. 4.2 x 1024 molecules of carbon dioxide, CO2
c. 3 x 1022 copper ions, Cu2+
Number of moles = Number of particles
6 × 1023
Calculating the number of moles from the number of particles
TB P147
2. Calculate the number of particles in a. 3 moles of carbon atoms, Cb. 0.75 moles of ammonia molecules, NH3
c. 25 moles of sodium chloride, NaCl
Extension Question! How many atoms are there in 0.75 moles of
ammonia molecules?
Number of moles = Number of particles
6 × 1023
Molar MassThe mass of one mole of any substance is
called the molar mass.
The molar mass is the relative atomic mass of the element in grams.
For Substances Consisting of Atoms
The molar mass is the relative molecular mass of the substance in grams.
For Substances Consisting of Molecules
The molar mass is the relative formula mass of the substance in grams.
For Substances Consisting of Ions
Calculating the number of moles from the molar massNumber of moles =
Mass (in g)
Molar mass (in g)
TB P150
1. (a) How many moles of atoms are contained in 32 g of oxygen atoms?
4. (c) Calculate the mass of 4 mol of oxygen molecules, O2?