Answer :
The number Beryllium chloride consumed is calculated as follows
write equation for reaction
that is BeCl2 + Mg -----> MgCl2 +Be
find the moles of MgCl2 produced
moles =mass/molar mass of MgCl2
= 987.5g/95 = 10.39 moles
by use of mole ratio between BeCl2 to Mgcl2 which 1:1 therefore the moles of BeCl2 is also 10.39moles
mass of BeCl2 = moles x molar mass
that is 10.39 x80 = 831.2
write equation for reaction
that is BeCl2 + Mg -----> MgCl2 +Be
find the moles of MgCl2 produced
moles =mass/molar mass of MgCl2
= 987.5g/95 = 10.39 moles
by use of mole ratio between BeCl2 to Mgcl2 which 1:1 therefore the moles of BeCl2 is also 10.39moles
mass of BeCl2 = moles x molar mass
that is 10.39 x80 = 831.2