Question

Il 15 a Counting Unit 1 pair of objects 2 objects 1 dozen objects = 12 objects 1 gross of objects = 144 objects 1 mole of objects = 6.022 x 10” objects INFORMATION The number of objects in a mole (6.022 x 1025 is so important to this aspect of chemistry it is given a name. The number of objects in mole is called Avogadro's number (6.022 x 10" objects per mole). The unit for Avogadro's number is "objects/mol". Avogadro's number is determined by counting the number of atoms in exactly 12 g of carbon-12. The mass of one mole of an object is called the molar mass and has units of g/mol. 1) How many "C atoms are there in 12 g of carbon-12? 2) How many moles of C are there in 12 g of carbon-12? 3) As a group, in or two complete and grammatically correct sentences, write a definition of a mole (not the furry animal). 4) How many molecules of CO2 are there in 44.01 g of CO2? 5) How many moles of CO2 are there in 44.01 g of CO2? Hint: 1 mole of objects = 6.022 x 10" objects

Answer 1

I 1. The molar mass of 126 atoms I is = 12 g So, in 12 g Carbon- 12 & the no E of c atoms = 1 mol 12 atoms. = 6.022 x 1023 c atoms. 1 2 The no. of moles of 12 in 12 g of C-12 = 1 mol As molar mass of carbon atom (62) = 12 g/mol One moles of any substa- nee can be defined as the no. of constitute particles (atoms, molecules, ions ete) of that substance that I are equal to the no. of particles of 12 g of the isotope.

A molar mass of co2 = 44.01 g Thus, in 44.01 g of cog, the no. of molecules of con = 1 mol coa molecule = 6:022 x 1023 molecule of con 5 Now, as, 1 mole of objects = 6:022 x 1023 objects Thus, 6.022 x 10 23 molecule of coz = 1 mol of coa