Question

1. One of the substances in a new alkaline battery is composed of 63.0% manganese and 37.0% oxygen by mass. Determine the empirical formula of the compound in the battery.

Answer 1

Divide each % value by respective atomic mass  
Mn = 63.0/54.94 = 1.1467 
O = 37/16 =2.3125 
Divide by smaller value 
Mn = 1  
O = 2.3125/1.1467 = 2 Empirical formula = MnO2