Experiment 25 Essay

Submitted By bcb11c
Words: 1375
Pages: 6
Open Document
Experiment 9: Calorimetry & Hess’s Law Date Performed: 11/01/2012 Name: Bria Burris
Date Submitted: 11/8/2012 Partner Name: Bianca Idas Chemistry 1045L-Sec#46
Zhang, Xiaoguang

Purpose
The purpose of this experiment was to test and expand on the knowledge of Calorimetry and how energy and heat moves from a system to the surroundings and vice versa. The purpose of this experiment is also to closely study the concept of enthalpy and specifically the enthalpy of a reaction.
Experimental Procedure
Dillon, Stephanie. “Calorimetry & Hess’s Law.” Laboratory Manual. Pearson Publishing, 2012, pp. 163-177.
Data and Results
Part A Data Part A | Trial 1 | Trial 2 | Exact volume of cold water | 50mL | 50 mL | Temperature of cold water | 22◦C | 22◦c | Exact Volume of Hot water | 50mL | 50mL | Temperature of Hot water | 46.5◦C | 57◦C |
Part A Calculations Trial 1 Trial 2 Mass of cold water | 50g | 50g | Tf from graph by extrapolation | 29.8℃ | 31.2℃ | ∆T of Cold water | 7.8℃ | 9.2℃ | ∆T ofHot Water | -16.7℃ | -25.8℃ | qHW | -3490.3 J | -5392 J | qCW | 1630.2 J | 1922.8 J | qcal | 1860.1 J | 3469.2 J | Ccup | 238.5 J | 377.1 J |
What ∆T should be used? Cold Water
Part B Data Part B | Trial 1 | Description of sample | Clear HCl solution and silver colored Mg strips. After experiment Mg strips no longer present. | Exact Volume of HCl | 100mL | Initial Temperature of HCl | 22◦C | Exact Mass of Mg | 0.112g |

Part B Calculations Tffrom graph by extrapolation | 25.2℃ | Mass of HCl solution | 100g | ∆Tcw for HCl | 3.2℃ | qHCl | 1337.6 J | qcal | 985 J | qrxn | 2322.6 J | ∆Hrxn for Mg | 503.8 kJ/mol |

Balanced Equation Part B:
2H⁺ (aq) + Mg(s) ->Mg²⁺ (aq) + H₂ (g)

Part C Data Part C | Trial 1 | Description of sample | Sample is a clear color. No color | Exact Volume of 100 mL HCl | 100mL | Initial Temperature of HCl | 22◦C | Exact mass of MgO | .5g |

Part C Calculations Tf from graph by extrapolation | 23.5℃ | ∆Tcw for HCl | 1.5℃ | qHCl for the cup | 627 J | qcal for the cup | 461.7 J | qrxn | 1088.7 J | ∆Hrxn for MgO | 87.8 kJ/mol |

Balanced Equation Part C
2H⁺ (aq) + MgO(s) ➝Mg²⁺(aq) + H₂O(g)

Graphs

Calculations
Part A Calculations
*Using Trial 1 data for calculations
Mass of Cold Water:
Mass of Cold Water = Volume of Cold water ×Density of Water
50mL×1g1ml=50g
∆THW for Cold water:
∆THW for Cold water= Tf-TI
29.8℃-22℃=7.8℃
∆THW for Hot water:
∆THW for Cold water= Tf-TI
29.8℃-46.5℃=-16.7℃
qHW for Hot Water: qHW for Hot Water=mc∆THW
50g4.18Jg℃-16.7℃=-3490.3 J qCW for Cold Water: qCW for Cold Water=mc∆Tcw
50g4.18Jg℃7.8℃=1630.2 J qcal for the cup: qcal= qHW-qCW
-3490.3-1630.2=1860.1 J
Ccup for the cup:
Ccup for the cup= qcal∆T
1860.1J7.8=238.5 J
Part B Calculations
Mass of HCl solution: Volume of Cold water ×Density of Water
100mL×1 g1mL=100g
∆TCW for HCl:
Tf-TI=∆T for HCl
25.2℃-22℃=3.2℃
qHCl for HCl: mc∆T=qHCl 100g4.18Jg℃3.2℃=1337.6 qcal for HCl:
Ccup× ∆THCl=qcal
307.8J×3.2=985J
qrxn: qHCl+qCal=qrxn 1337.6+985=2322.6J
∆Hrxn for Mg: qrxnnMg=∆Hrxn 2322.6J0.00461 mol=503817J=503.8Kj/mol nmol=0.112g×1 mol of Mg24.31g of Mg=0.00461 mol
Part C Calculations
∆TCW for HCl:
Tf-TI=∆T for HCl
23.5℃-22℃=1.5℃
qHCl for HCl: mc∆T=qHCl 100g4.18Jg℃1.5℃=627J qcal for the cup:
Ccup×∆THCl=qcal
307.8×1.5=461.7J qrxn: qHCl+qCal=qrxn
627J+461.7J=1088.7J
∆Hrxn for MgO: qrxnnMg=∆Hrxn 1088.7J0.0124 mol=87798J=87.8kJ/mol nmol=0.5g×1 mol of MgO40.31g of MgO=0.0124 mol

Conclusion To conclude, Part A, Part B, and Part C all went successfully they all cooled in the end with the temperature going from high to low. In Part A cold water was
Show More

Related Documents: Experiment 25 Essay

Phytochromes Cause Differences In Lettuce Seed Germination

Craig Evans Bio 102-014 Phytochromes cause differences in lettuce seed germination Abstract Plants use photoreceptors called phytochromes to discern what wavelength of light is being absorbed and respond accordingly. This experiment tests what happens when three different types of lettuce seeds are exposed to white light, red light, far-red light, and darkness. Lettuce seeds were placed in petri dishes and exposed to different wavelengths of light. The number or germinated seeds…

Words 1256 - Pages 6

labreport erroranalysis phy2048 Essay

Maria Saavedra 1/29/2015 Introduction: The error analysis experiment was to determine the acceleration of a free fall object. This experiment is also to become acquainted with types of error and statistical methods for analyzing one's data and for estimating its accuracy. It is also to determine how close is the value of acceleration to the accepted value (9.81m/s/s) when the experiment is done multiple times. Methods: For this experiment Logger pro was used, a photogate were used to collect the…

Words 465 - Pages 2

Respirometer 6 Lab Report

beads we put in the tube and placed all the beads on a paper towel. This beads removed were arranged for the experiment 3 For the fourth experiment which is the respirometer four, we put 25 ml of water in the 50ml of the graduated tube and from there we proceeded to drop 25 germinating corn seeds. To be able to determine the volume of water that has been sent off, which we discovered that the volume of the water dispatched is equal to the volume of corn. After this we proceeded to recording the…

Words 362 - Pages 2

Stats: Chemical Kinetics and Reaction Essay

Experiment X Kinetics of the Decomposition of Hydrogen Peroxide Name: Will Milliken Student Number: 6771898 Partner’s Name: Chris Cariou Course Code: CHM 2330 Due Date: January 28, 2014 Table of Contents Objective………………………………………………………………………………………………………………………………..3 Introduction……………………………………………………………………………………………………………………………3 Procedure………………………………………………………………………………………………………………………….……5 Table 1…………………………………………………………………………………………………………………………6…

Words 2450 - Pages 10

Essay on Bio PH LAB

environment and the interior of the cell plays a crucial role in the effects of diffusion, as higher concentrations of molecules tend to move towards lower areas of concentration as the molecules bump into each other and sub-sequentially spread out. This experiment will involve the use of dialysis tubing to mimic a cell body and reflect the permeability of its membrane, then staging the cells containing various degrees of solution percentage of distilled water and glucose into environments of distilled water…

Words 593 - Pages 3

Extra-Sensory Perception In Titan's Twelfth

people whom are simply "more in tune" with their abilities than others (Harris 1-2). Additionally, the majority who believe in ESP are believers because of personal experience, but some hold their position based upon "anecdotal evidence," which are experiments and studies (Harris 1-2).…

Words 631 - Pages 3

Questions On Social Psychology

1) The point is to explain why experiments are used in social psychology. People are unaware of why they act in a certain way or change beliefs in one direction or another. He found that “nearly perfect” people become more attractive after they commit a blunder, while ordinary people become less attractive after committing the same blunder. 2) The experiment conducted used three different initiation processes from sever initiation to no initiation at all. They believed that people who expended greater…

Words 581 - Pages 3

Journal Of Public Economics: Contents Lists Available At Science

(2011) 344–350 Contents lists available at ScienceDirect Journal of Public Economics j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / j p u b e Small matches and charitable giving: Evidence from a natural field experiment☆ Dean Karlan a,b,f, John A. List b,c,d,⁎, Eldar Shafir b,e a Yale University, Department of Economics, 27 Hillhouse Avenue, New Haven CT 06511, United States Innovations for Poverty Action c The University of Chicago, Department of Economics…

Words 5583 - Pages 23

Chemical Kinetics and Rate Constants Essay

Experiment 7 Worksheet THE KINETICS OF HYDROLYSIS OF tert–BUTYL CHLORIDE Write a brief aim for the experiment: 1. To determine the first order rate constants for the HYDROLYSIS OF tert–BUTYL CHLORIDE (TBC) reaction at the three difference temperatures: 25°C,35°C , 47°C. We need to make out of date of experiments in 25°C,35°C by using conductimetric methods and the date in 47°C already has given. Then we need to make graphs by Excels to get the rate constants. 2. To use these rate constants to determine…

Words 715 - Pages 3

Mystery of the Philadelphia Experiment Essay

Mystery of the Philadelphia Experiment One day in the year 1943, a man named Carlos Miguel Allende claims to have seen a ship turn invisible! He was on a navy boat by the name of the SS Andrew Furuseth. He spotted a ship named the USS Eldridge in the distance. He described the scene he had witnessed by explaining how a green fog began to surround the ship. In just a short amount of time only the hull was visible, and then it had completely disappeared. Not only had the ship turned invisible, but…

Words 1768 - Pages 8