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Title: Calculate the molar enthalpies of reaction for the reactions occurring in Parts Post by: priyah on May 2, 2015 Part A
Mass of Mg(s) 0.31 g Initial temperature of calorimeter contents 24.1 ºC Final temperature of calorimeter contents 36.8 ºC Part B Mass of MgO(s) 1.22 g Initial temperature of calorimeter contents 24.0 ºC Final temperature of calorimeter contents 31.9 ºC Calculate the molar enthalpies of reaction for the reactions occurring in Parts A and B Help please! :( Title: Re: Calculate the molar enthalpies of reaction for the reactions occurring in Parts Post by: psyche360 on May 2, 2015 The heat, Q, would be given by:
Q = -(mass of mixture in grams) * (heat capacity of mixture in joules per gram per degree Celsius) * (change in temperature in degrees Celsius) The molar enthalpy is then Q/number of moles of solute. You can calculate the change in temperature and the moles of solute, but you need the mass of solute plus HCl and the heat capacity of the mixture. You should have measured the former and the latter would have to be given to you or be looked up. Title: Re: Calculate the molar enthalpies of reaction for the reactions occurring in Parts Post by: habiba on May 2, 2015 According to an internet source, the answer to this question is -601.6 KJ/mol Mg reacted
Title: Re: Calculate the molar enthalpies of reaction for the reactions occurring in Parts Post by: bio_man on May 2, 2015 I've answer your question below, enjoy :D
Title: Re: Calculate the molar enthalpies of reaction for the reactions occurring in Parts Post by: Arii_bell on May 2, 2015 Hey bio_man,
I was looking over your answer and for some reason i am not getting the same answers as you when I calculate them. Anyway you could explain it a little further for me? Thanks Title: Re: Calculate the molar enthalpies of reaction for the reactions occurring in Parts Post by: bio_man on May 2, 2015 No idea. It's not my assignment. Feel free to reject my post.
Title: Re: Calculate the molar enthalpies of reaction for the reactions occurring in Parts Post by: Arii_bell on May 3, 2015 Content hidden
Title: Re: Calculate the molar enthalpies of reaction for the reactions occurring in Parts Post by: bio_man on May 3, 2015 So, solved now? :angel:
Title: Re: Calculate the molar enthalpies of reaction for the reactions occurring in Parts Post by: Arii_bell on May 4, 2015 Yes Everything should be good!
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