Respuesta :
According to law of conservation of mass, mass can neither be destroyed nor created in a chemical reaction. Thus, sum of masses of reactants must be equal to sum of masses of products in a reaction.
The chemical reaction is as follows:
[tex]2Cu+O_{2}\rightarrow 2CuO[/tex]
Here, sum of masses of Cu and oxygen gas should be equal to CuO formed.
[tex]2m_{Cu}+m_{O_{2}}=2m_{CuO}[/tex]
Thus, mass of oxygen will be:
[tex]m_{O_{2}}=2(572.4-508.4)g=128 g[/tex]
This can be further proved as follows:
The balanced chemical reaction is as follows:
[tex]2Cu+O_{2}\rightarrow 2CuO[/tex]
Here, 2 moles of Cu completely reacts with 1 mole of [tex]O_{2}[/tex] to give 2 moles of [tex]CuO[/tex].
Thus, 1 mole of Cu reacts with 0.5 moles of [tex]O_{2}[/tex] .
The mass of Cu is 508.4 and molar mass is 63.546 g/mol, number of moles can be calculated as follows:
[tex]n=\frac{m}{M}=\frac{508.4 g}{63.546 g/mol}=8 mol[/tex]
Thus, number of moles of [tex]O_{2}[/tex] reacting will be:
[tex]n_{O_{2}}=8\times 0.5 mol=4 mol[/tex]
Molar mass of oxygen molecule is 32 g/mol thus, mass can be calculated as follows:
m=n×M=4 mol×32 g/mol=128 g/mol
This satisfies the law of conservation of mass.
