## Chemistry and Chemical Reactivity (9th Edition)

$B_5H_7$
Atomic weights (g/mol): $B: 10.81,\ H: 1.008$ In 100.0 g: B: $88.5\ g \div 10.81= 8.19\ mol$ H: $11.5\ g\div 1.008 = 11.4\ mol$ Normalizing by the smallest amount of moles: B: $8.19/8.19= 1.0$ H: $11.4/8.19=1.4$ To get integer numbers, we multiply each proportion by 5 which yields: Empirical formula $B_5H_7$