How many formula units make up 22.6 g of magnesium chloride (mgcl2)?

            Formula Units  =  1.42 × 10²³

Solution:

Step 1: Calculate Moles using following formula,

                                     Moles  =  Mass ÷ M.mass

As,

                                     M.mass of MgCl₂  =  95.2 g.mol⁻¹

Putting values,

                                     Moles  =  22.6 g ÷ 95.2 g.mol⁻¹

                                     Moles  =  0.237 mol

Step 2: Calculate number of Formula Units using following formula,

                                     Formula Units  =  Moles × 6.022 × 10²³

Putting values,

                                     Formula Units  =  0.237 × 6.022 × 10²³

                                     Formula Units  =  1.42 × 10²³

the correct answer is:

a. formation of precipitation

water at room temperature is flowing through a pipe with pressure taps located 10 ft apart along one section of the pipe, which are connected to a mercury (s=13.6) manometer.