Question

An old container has 188g solid substance. Analysis of this solid showed that the solid is calcium chloride. How many molecules of calcium chloride are present in the container?

Answer 1

mass of solid = 188 g

molar mass of Calcium chloride = CaCl2 = 110.98 g/mole

number of moles of CaCl2 = mass/molar mass =188/110.98 = 1.694 moles

number of moles of CaCl2 = 1.694 moles

one mole of compound contains Avagadro number of molecules [ Avagadro number = 6.023x10^23]

one mole of CaCl2 contains = 6.023 x10^23 molecules of CaCl2

1.694 moles of CaCl2 contains =?

                                                 = 1.694 x6.023x10^23/1 = 10.203x10^23

number of molecules present in CaCl2 = 1.02x10^24 molecules.