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

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation: