I need to find the energy released (in kilojoules) with the reactiong of this: 2 Al(s) + 3 Cl2(g) = 2 AlCl3(s) ∆H°= -1408.8 kJ when using 5.00 grams of Al. I know this is basic chemistry, but I'm stuck If someone could just help point me in the right direction, I will solve the problem. I appreciate it (I know these forums aren't for homework help, but I really am stuck and desperate )
okay, I just had a sudden inspiration for an idea of how to do this. I'll explain below, can someone tell me if I did it right? I divided 5.00g Al by 26.98 g/mol to get the # of moles, that came out to be .18532 mol I divided that by 2 because there are 2 mols of Al, that came out to be .09266 (roughly) I then divided the ∆H° (-1408.8 kJ) by the # of moles (.093) to get the final answer of -15144 It made sense as I was doing it....
I'm one of the top of my class and I understood diddly squat of that! well... i just didn't get it... I will someday... alas.. crappy teacher or it ain't for GCSE level... but *basic* ... basic is what's the symbol for sodium, or why are the groups the way they are etc... </rantage>
Sorry I can't help, but don't feel bad about asking in the forums... I passed many a physics test based on help from the good people that freqent these forums. Although it kind of makes me feel a little stupid for not knowing, and seeing how smart they are, but then I think to myself... I can juggle, and in the end, isn't that all that really matters?
seems about right, but your final number is in jules, right? Not kilojules? Edit: I don't think I'm reading the delta-Hº right. Is that change in heat? Sorry, I'm trying
Your problem should look a bit like this 5.00g | 1 mole Al | 2 moles AlCl3 | -1408.08 kJ ____________________________________ = -260.948851 Kj ----- | 26.98g - | 2 moles Al -- | mole Hopefully that formats alright. With significant figures, your answer is -261 Kj
