Calorimetry

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risa
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Calorimetry

Post by risa »

The enthalpy of neutralization of a newly discovered compound, HX, was determined using a styroball calorimeter. The calorimeter was first calibrated using 13.00 mL of 0.104 M HCl and 11.29 mL of 0.125 M KOH (AH = -55.85 kJ/mol) and a temperature rise of 4.6 °C was recorded. Using the same calorimeter, 7.58 mL of 0.151 M of HX was reacted with 9.60 mL of 0.125 M NaOH and the temperature changed from 25.9 °C to 23.4 °C.
a. What is the heat capacity of the calorimeter?
b.What is the experimental enthalpy (in kJ/mol) for the neutralization reaction
between HX and NaOH?

I just need someone to explain how can I compute both questions and then I will be up for the rest. Thank you very much.
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ChenBeier
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Re: Calorimetry

Post by ChenBeier »

Here are some basics

https://www.wikihow.com/Calculate-Heat-Capacity

For the first calculate the moles used in the neutralisation. There is some excess of one chemical. From this the heat capacity.
Backwards use the second pair to get the Experimental enthalpy.Also here is excess of one chemical.

There is also an error. In the second neutralisation is a temperature decrease instead of temperature increase.
risa
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Re: Calorimetry

Post by risa »

For the heat capacity, should I only calculate reaction of HX and NaOH, disregarding KOH and HCl?
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ChenBeier
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Re: Calorimetry

Post by ChenBeier »

No, first get the heat capacity of HCl and KOH. This is the calibration of the device. With the second neutralisation you calculate the unknown HX and NaOH.
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