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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: 2n01k3 on November 24, 2011, 07:08:27 AM

Title: calorimetry
Post by: 2n01k3 on November 24, 2011, 07:08:27 AM

in the reaction 10mL of 1M NaOH + 5mL of 1M HCl (adiabatic)
given change in temp=2.1°C (temp initial is the temp of NaOH, temp final is acquired after the addition of HCl)
find: qrxn, qcal, Ccal
i used the molarity to find the number of moles for each reactant. i think i should use the equation: dh=qrxn/nrxn but i don't know what nrxn means. is it the total number of moles?
0.01mol (NaOH) + 0.005(HCl) = 0.015mol = nrxn? is this correct?
given dH formation of water=-55.8kJ/mol
help please. thanks in advance:)

Title: Re: calorimetry
Post by: Borek on November 24, 2011, 08:42:35 AM

Hint: this is a limiting reagent problem.

Title: Re: calorimetry
Post by: Vidya on November 24, 2011, 09:51:50 AM

as indicated by Borek
you need to select a  limiting reactant and nrxn is the number of moles of water formed during the reaction.You can calculate nrxn by using limiting reactant