
Sarah S. answered 01/29/16
Tutor
4.9
(540)
SAT/ACT, Chemistry, Biology, and Math -- 15 yrs; 200+ pt improvement
Hi Marlene,
1) Find the formula from the name:
Pb4+ and O2- (swap and drop charges, then reduce) = PbO2
2) Calculate the molar mass from the periodic table
Pb = 207.2 g/mol
2 x O = 2 x 16 g/mol
Total = 239.2 g/mol
3) Multiply moles by molar mass to cancel 'mol' unit
1.23 mol x 239.2 g/mol = 294.216 g
4) Round answer to correct sig figs
294 g
Hope this helps!