Answer to Question #64947 in General Chemistry for francis

Question

14.34 g of an oxide of lead was heated in a stream of dry hydrogen, 12.42 g of lead was obtained. Relative atomic masses of oxygen and lead are 16 and 207 respectively.
1. How many grams of oxygen were presthe oxide?
2. Calculate the number of moles of oxygen atoms present.

Answer 1

PbO + H2 = Pb + H2O
We use the law of equivalence
m(O) / Мeq (О) = m(Pb) / Мeq (Pb)
In these compounds with one mole of lead atoms connected one mole of oxygen atoms

m(O) = m(Pb) x Мeq (О) / Мeq (Pb)
m(O) = 16 g/mol x 12.42 g / 207 g/mol = 0.96 g
Determine the quantity of the substance in oxygen 0.96 g
n(O) = m (O) / M (O) = 0.96 / 16 = 0.06 mol