When silver oxide was heated, 43.2 g of silver and 3.2 g of oxygen were formed. What is the mass of the decomposed oxide?

Given:
m (Ag) = 43.2 g
m (O2) = 3.2 g

To find:
m (Ag2O) -?

Decision:
1) Write the equation of a chemical reaction:
2Ag2O = (tOC) => 4Ag + O2 ↑;
2) It is necessary to use the law of conservation of mass (Lomonosov-Lavoisier’s law), which states that the mass of substances that have entered into a reaction is equal to the mass of the substances formed;
3) m (Ag2O) = m (Ag) + m (O2) = 43.2 + 3.2 = 46.4 g.

Answer: The mass of Ag2O is 46.4 g.