Use the values below to answer the question that follows. ΔHsub of MgΔHf of MgCl2(s)1st ionization energy of Mg2nd ionization energy of MgBond energy of Cl2 Electron affinity of Cl=147.7 kJ/mol=−641.3 kJ/mol=737 kJ/mol=1450.7 kJ/mol=242 kJ/mol=−349 kJ/mol For the values given above, "sub" stands for sublimation and "f" stands for formation. What is the lattice energy (lattice enthalpy) of MgCl2? Your answer should have three significant figures.

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation: