For the following, tell whether the process is endothermic or exothermic. a) A l

Question

For the following, tell whether the process is endothermic or exothermic. a) A lighter burns. ______. b) Water drops evaporate from your skin. _____. c) Water vapors condense on a cold surface. _____. Consider the following reaction: Fe_2 O_3(s) + 2AI(s) rightarrow Al_2 O_3(s) + 2 Fe(s) delta H = -852 kJ a) Is the reaction endothermic or exothermic? (circle one) b) How much heat is evolved when 25 g of Fe_2 O_3 and 22 g of Al react to completion? c) Calculate for the reaction: 2Al_2 O(s) + 4Fe(s) rightarrow 2Fe_2 O_3(s) + 4Al(s)

Explanation / Answer

Ans. 3. (a) For the formation of Al2O3 from Fe2O3 is exothermics as the value of delta H is negative that indicates the forward reaction is exothermic in nature.

(b) molar mass of Fe2O3 = 159.69 g/mol

159.69 g Fe2O3 release 852KJ of heat

25g Fe2O3 release 852 * 25 / 159.69 = -133 KJ

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