calculate the number of particles in each of the following a. 18 gram of O2 molecules b. 0.1 mole of Calcium atomic

3.39 x 10²³ particles

6.02 x 10²²particles

Explanation:

The problem here entails we find the number of particles in the given substances.

From the mole concept;

          1 mole of a substance contains 6.02 x 10²³ particles

a. 18g of O₂;

 We first find the number of moles of this substance first;

       Number of moles  =  

  Molar mass of O₂   = 2(16) = 32g/mol

      Number of moles  =   = 0.56mole

 So;

             1 mole of a substance contains 6.02 x 10²³ particles

            0.56 mole of  O₂ will contain 0.56 x 6.02 x 10²³ particles

                                                                   = 3.39 x 10²³ particles

b. 0.1mole of calcium atom:

        1 mole of a substance contains 6.02 x 10²³ particles

       0.1 mole of the substance will contain 0.1 x  6.02 x 10²³ particles

                                                                         = 6.02 x 10²²particles

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.