Answer:
3 g of H₂
Step-by-step explanation:
The balanced equation for the reaction is given below:
Cr₂O₃ + 3H₂ —> 2Cr + 3H₂O
Next, we shall determine the masses of Cr₂O₃ and H₂ that reacted from the balanced equation. This can be obtained as follow:
Molar mass of Cr₂O₃ = (52×2) + (16×3)
= 104 + 48
= 152 g/mol
Mass of Cr₂O₃ from the balanced equation = 1 × 152 = 152 g
Molar mass of H₂ = 2 × 1 = 2 g/mol
Mass of H₂ from the balanced equation = 3 × 2 = 6 g
SUMMARY:
From the balanced equation above,
152 g of Cr₂O₃ reacted with 6 g of H₂
Finally, we shall determine the mass of H₂ needed to covert 76 g of Cr₂O₃. This can be obtained as follow:
From the balanced equation above,
152 g of Cr₂O₃ reacted with 6 g of H₂.
Therefore, 76 g of Cr₂O₃ will react with = (76 × 6) / 152 = 3 g of H₂
Thus, 3 g of H₂ is needed to convert 76 g of Cr₂O₃.