Question

How many moles are contained in each of the following?

A. 27.0 g Ca

Express your answer using three significant figures.

B.

5.00 g S

C.

36.0 g H2O

D.

110.0 g O2

Answer 1

A. 27.0 g Ca

Gram atomic weight of Ca(G.A.Wt)   = 40g/mole

no of moles of Ca   = W/G.A.Wt

                                 = 27/40   = 0.675moles

B. 5.00 g S

Gram atomic weight of S(G.A.Wt) = 32g/mole

no of moles of S   = W/G..A.Wt

                              = 5/32   = 0.156moles

C. 36.0 g H2O

Gram molecular weigh of H2O (G.M.Wt) = 18g/mole

no of moles of H2O   = W/G.M.Wt

                                   = 36/18    = 2.00 moles

D. 110.0 g O2

Gram molecular weigh of O2 (G.M.Wt)   = 32g/mole

no of moles fo O2   = W/G.M.Wt

                                = 110/32   = 3.44moles