Determine the heat given off to the surroundings when 9.873 g of aluminum reacts according to the equation 2Al + Fe2O3 → Al2O3 + 2Fe, ΔH°rxn= -849.1 kJ/mol.

Respuesta :

Answer : The heat given off to the surroundings will be, -155.38 KJ

Solution : Given,

[tex]\Delta H^o_{rxn}=-849.1KJ/mole[/tex]

Mass of aluminium = 9.873 g

Molar mass of aluminium = 27 g/mole

First we have to calculate the moles of aluminium.

[tex]\text{ Moles of Al}=\frac{\text{ Mass of Al}}{\text{ Molar mass of Al}}=\frac{9.873g}{27g/mole}=0.366moles[/tex]

The given balanced reaction is,

[tex]2Al+Fe_2O_3\rightarrow Al_2O_3+2Fe[/tex]

From the reaction, we conclude that

2 moles of aluminum releases heat energy = -849.1 KJ

0.366 moles of aluminium releases heat energy = [tex]\frac{-849.1KJ}{2moles}\times 0.366moles=-155.38KJ[/tex]

Therefore, the heat given off to the surroundings will be, -155.38 KJ