Final answer:
The balanced chemical equation for the reaction of the reduction of copper oxide by hydrogen is Cu2O(s) + H2(g) → 2Cu(s) + H2O(g), inferred from the stoichiometric analysis of the masses of copper and water formed.
Step-by-step explanation:
The reaction in question involves the reduction of a copper oxide by hydrogen. When copper oxide is heated in a stream of hydrogen, the oxide is reduced to copper metal, and water is formed. This is a redox reaction where hydrogen acts as the reducing agent. To write the balanced equation for the reaction, we need to determine the formula of the copper oxide. Since we have the masses of copper and water produced, we can use this information to deduce the formula of the oxide.
We start by converting the mass of water to moles. The molar mass of water (H2O) is 18.02 g/mol. Using the mass of water given:
(2.56 g H2O) / (18.02 g/mol) = 0.142 moles of H2O
Since water has two hydrogen atoms per molecule, this means there were 0.284 moles of hydrogen in the copper oxide. As hydrogen is in a 1:1 ratio with oxygen in water, there were also 0.142 moles of oxygen in the copper oxide.
Next, we convert the mass of copper to moles. The molar mass of copper (Cu) is approximately 63.55 g/mol. Using the mass of copper given:
(17.6 g Cu) / (63.55 g/mol) = 0.277 moles of Cu
Now that we have moles of copper and oxygen, we can determine the simplest whole number ratio to find the formula of the copper oxide. Since we have nearly twice as many moles of Cu as O, it suggests that the formula is likely Cu2O. Therefore, the balanced chemical equation for the reaction is:
Cu2O(s) + H2(g) → 2Cu(s) + H2O(g)