## Calorimetry

Chemistry and homework help forum.

Organic Chemistry, Analytical Chemistry, Biochemistry, Physical Chemistry, Computational Chemistry, Theoretical Chemistry, High School Chemistry, Colledge Chemistry and University Chemistry Forum.

Share your chemistry ideas, discuss chemical problems, ask for help with scientific chemistry questions, inspire others by your chemistry vision!

Please feel free to start a scientific chemistry discussion here!

Discuss chemistry homework problems with experts!

Ask for help with chemical questions and help others with your chemistry knowledge!

Moderators: Xen, expert, ChenBeier

risa
Newbie
Posts: 2
Joined: Mon May 23, 2022 12:47 am

### Calorimetry

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.
ChenBeier
Distinguished Member
Posts: 1210
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

### Re: Calorimetry

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
Newbie
Posts: 2
Joined: Mon May 23, 2022 12:47 am

### Re: Calorimetry

For the heat capacity, should I only calculate reaction of HX and NaOH, disregarding KOH and HCl?
ChenBeier
Distinguished Member
Posts: 1210
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

### Re: Calorimetry

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.