Question

Determine the heat given off to the surroundings when 9.0 g of aluminum (fm = 26.98) reacts according to the equation 2al + fe2o3 → al2o3 + 2fe, δh°rxn= –849 kj/mol

Answer 1

Hey there!:

Number of moles:

Molar Mass Al = 26.98 g/mol

n = mass / molar mass

n = 9.0 / 26.98

n = 0.3336 moles of Al

Given the reaction :

2 Al + Fe2O3 = Al2O3 + 2 Fe

From the equation, 2 moles of Al give off 849 kJ of heat :

Actual heat given off :

0.3336 / 2 * 849 =

0.3336 / 1698 = 1.4*10² Kj

Hope that helps!