Answer:
0.21 mole of C8H18.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
2C8H18 + 25O2 —> 16CO2 + 18H2O
Next, we shall determine the number of mole of C8H18 that reacted and the number of mole water (H2O) produced from the balanced equation.
This is illustrated below:
From the balanced equation above,
2 moles of C8H18 reacted to produce 18 moles of H2O.
Finally, we shall determine the number of mole C8H18 needed to produce 1.90 moles of H2O.
This can be obtained as follow:
From the balanced equation above,
2 moles of C8H18 reacted to produce 18 moles of H2O.
Therefore, Xmol of C8H18 will react to produce 1.90 moles of H2O i.e
Xmol of C8H18 = (2 × 1.90)/18
Xmol of C8H18 = 0.21 mole
Thus, 0.21 mole of C8H18 is needed for the reaction.