Thermochemistry

 

background [prelab assignment (15 points) due at the beginning of lab] 

 Design / describe an experimental method to accomplish the purpose of the lab using the below materials

sketch a data table for the corresponding experiments 

 

 purpose

 determine the specific heat of an alloy

determine ΔH to dissolve solid sodium hydroxide in water

determine ΔH to melt ice  (see: textbook; ch. 10; Explore / explain:  phase change;  Part C  

materials

 coffee cup caloriometer

hot plate; beaker; water; thermometer; electronic balance; graduated cylinder

solid alloy; sodium hydroxide 

methods / data analysis

 student design

 

NGSS chemistry textbook; ch. 10  ---  lab activity, but score as CW / HW assignment   

Explore / explain:  heat capacity  [6 points]

Part A (lab).  Exploring heat cacpacity.  Proesss & Procedure; # 4.   Stop & think; # 1, 3, 4  

Part B.  Explaining heat capacity.  Process & Procedure; # 2.  Reflect & connect; # 2 

Explore / explain:  thermal expansion.  Part A:  exploring thermal expansion (pseudo-lab; 5 points)

Process & Procedure; # 2; in lieu of teacher ball & ring demo, take notes of video of heating the ball versus video of heating the ring) , 4, 7  (take notes of video in lieu of lab & use TE lab data)  

 Stop & think; # 2

take notes on thermal expansion of liquid annimation

Content of lab report [35 points]

results (20 points) 

 data table

data analysis; show your work

Δ H to disolve solid NaOH in water in kJ/mol

Δ H to melt ice / water in kJ/mol 

specific heat of metal  

discussion (15 points)

error analysis: What is a non-trivial reason for the difference between the theoretical (include its value - either calculate or find a citation) versus experimental value of the ΔH to dissolve NaOH in water  ?  

describe the relationship between the final temperature (in a system with a hot metal added to water at room temperature) as a function of the specific heat of a metal; justify / rationalize your response using mathematics. 

describe / list two NGSS science & engineering practices that correlates to an aspect of this laboratory activity; provide an example in the lab & this lab report that meets these practices