Answer: 104 g
Explanation: reaction Cr2O3 + 3 H2 ⇒ 2 Cr + 3 H2O
M(Cr2O3) = 150 g/mol, so n = m/M = 1.0 mol
Number of moles of H2 should be 3.0 moles and
It is much greater (150 g / 2.016 g/mol)
1 mol Cr2O3 produces 2 mol Cr.
Mass m= 2.0 mol· 52g/mol= 104 g
The balanced equation that illustrates the reaction is:
2C4H6 + 11O2 ......> 8CO2 + 6H2O
number of moles = mass / molar mass
number of moles of oxygen = 2.1 / 32 = 0.065625 moles
Now, from the balanced equation, we can note that:
11 moles of oxygen are required to produce 6 moles of water.
Therefore:
0.065625 moles of oxygen will produce:
(0.065625*6) / 11 = 0.03579 moles of water
number of moles = mass / molar mass
mass = number of moles * molar mass
mass of water = 0.03579 * 18 = 0.644 grams