Class Notes (835,500)
Canada (509,212)
Chemistry (274)
CHEM 120L (21)
Lecture

Calorimetry used to calculate the enthalpy of neutralization reactions.docx

16 Pages
752 Views
Unlock Document

Department
Chemistry
Course
CHEM 120L
Professor
Sue Stathopulos
Semester
Fall

Description
Calorimetry used to calculate the enthalpy of neutralization reactions November 18, 2013 Joshua Fernandez ID#: 2051 5215 Rachel Dillman Elizabeth Boyd Section 001 Introduction: Calorimetry is the science of measuring the change in heat in physical or chemical reactions. This is determined through a device called a calorimeter. A calorimeter is isolated from its surroundings, as to only find out the temperature inside. It works by two chemicals being mixed in the calorimeter, reacting together, and a thermometer being placed beforehand in order to measure the change in heat inside the calorimeter. This is not a sealed system; therefore the internal pressure has to equal the atmospheric pressure. (Hansen and Russell 2006). If this is the case, the final and initial pressures would have to be the same as well. The symbol, q, represents the gain or loss of heat in a system. Ergo, because the pressures do not change within the reaction, q, and ∆H, which represents the enthalpy change, will be the same (Hansen and Russell 2006). The lab also deals with neutralization reactions. A neutralization reaction is the reaction between an acid and base which results in the forming of a salt and water. This lab specifically deals with strong electrolytes. Strong electrolytes completely disassociate when placed in solution (Andriola, Singh, Lewis and Yu 2010). In this lab, the neutralization reactions of strong electrolytes will produce q= -55.90KJ/mol of the hydrogen ion (Thauer 1998). As previously stated, q equals the enthalpy change; therefore the enthalpy change is also -55.90 KJ/mol of the hydrogen ion (Thauer 1998). There is a negative sign present, which means the reaction is exothermic: heat has been released. Finally, the lab discusses neutralization reactions with weak electrolytes. Weak electrolytes only partially disassociate into ions (Andriola, Singh, Lewis and Yu 2010). That means the q and enthalpy change for the reaction will depend on the electrolyte itself, and can either be exothermic or endothermic. Therefore, the calculation for the heat of the reaction will help with distinguishing between strong and weak electrolytes. Experimental Procedure: “The experimental procedure used for this experiment was outlined in the CHEM 120L lab manual, experiment #4. The experiment was done with deviation. The concentrations of the chemicals used in the lab were different from those in the lab manual.) Experimental Observations: Part A: The neutralization reaction of NaOH and HCL Trial #1 Every Second(C) Every 10 Seconds(C) Every 30 Seconds(C) 27.4 38.3 37.5 29.3 38.3 37.2 32.5 38.1 37.1 35.7 38.0 37.1 38.1 38.1 37.0 38.2 37.0 37.0 37.1 36.9 36.9 Part A: The neutralization reaction of NaOH and HCL Trial #2 Every Second(C) Every 10 Seconds(C) Every 30 Seconds(C) 26.2 35.8 35.0 28.4 35.1 35.0 30.1 35.1 35.0 34.3 35.1 35.0 35.1 35.1 34.9 35.1 34.9 34.9 34.9 34.9 34.9 Part B: The neutralization reaction of NaOH and HNO3 Trial #1 Every Second(C) Every 10 Seconds(C) Every 30 Seconds(C) 25.1 40.1 39.9 30.2 40.0 39.9 31.3 39.9 39.8 34.8 39.9 39.8 38.1 39.9 39.6 39.9 39.6 39.1 38.9 38.9 38.9 Part B: The neutralization reaction of NaOH and HNO3 Trial #2 Every Second(C) Every 10 Seconds(C) Every 60 Seconds(C) 25.5 39.8 39.2 30.3 39.9 39.4 33.0 39.9 39.3 37.2 39.8 39.1 39.6 39.8 38.9 39.8 38.9 38.9 38.9 38.9 38.9 Part C: The neutralization reaction of NaOH and Phenol Trial #1 Every Second(C) Every 10 Seconds(C) Every 60 Seconds(C) 26.2 28.1 28.1 27.1 28.2 28.1 27.8 28.2 28.2 27.9 28.3 28.1 28.3 28.0 28.0 28.1 28.0 28.0 28.1 28.0 28.1 Part C: The neutralization reaction of NaOH and Phenol Trial #2 Every Second(C) Every 10 Seconds(C) Every 60 Seconds(C) 25.2 27.9 27.8 26.2 27.8 28.1 27.1 28.0 27.9 27.9 27.8 27.8 28.1 27.9 27.9 27.8
More Less

Related notes for CHEM 120L

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit