How many moles of mgci2 are there in 310 g of the compound? this question is not multiple choice. i have two blank boxes to put my answer in, one that says answer and the other one is labeled units.

Number of Moles are calculate by using following formula,

                                        Moles  =  Mass / M.mass     --- (1)

M.mass is calculated by adding the atomic masses of all elements present in molecule, Since, MgCl₂ contains one Mg (atomic mass = 24.3 g/mol) and two Cl atoms (atomic mass = 35.45 × 2 = 70.9 g/mol), So,

                            Molar mass = 24.3 g/mol  +  70.9 g/mol

                            Molar Mass of MgCl₂ = 95.2 g/mol

Now, putting values in eq. 1,

                                        Moles  = 310 g ÷ 95.2 g/mol

                                        Moles  = 3.256 moles