Determine the heat given off to the surroundings when 9.0 g of aluminum reacts according to the equation 2Al + Fe₂O₃ $\rarr$Al₂O₃ + 2Fe, $\Delta$H^$\circ$_rxn= -849 kJ/mol. A) 1.4 * 10² kJ B) 2.8 * 10² kJ C) 5.6 * 10² kJ D) 2.5 * 10³ kJ E) 7.6 * 10³ kJ

Question

Quizplus · Accepted Answer

The molar mass of aluminum (Al) is approximately 27 g/mol. For 9.0 g of Al, the moles of Al are 9.0 g / 27 g/mol = 0.333 mol. The reaction involves 2 moles of Al, so the heat given off is (0.333 mol / 2 mol) * 849 kJ/mol = 141.5 kJ, which is approximately 1.4 * 10^2 kJ.

Determine the Heat Given Off to the Surroundings When 9 →\rarr→

Determine the Heat Given Off to the Surroundings When 9 $\rarr$