How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Scott Your Own Question

Scott
Scott, MIT Graduate
Category: Homework
Satisfied Customers: 3040
Experience:  MIT Graduate (Math, Programming, Science, and Music)
3546829
Type Your Homework Question Here...
Scott is online now
A new question is answered every 9 seconds

Module 5 Lab Thermodynamics and Gas Laws 3-1 Endothermic

Customer Question

Module 5 Lab: Thermodynamics and Gas Laws


3-1: Endothermic vs. Exothermic


In various chemical processes, such as reactions and the dissolving of salts, heat is either absorbed or
given off. This is called enthalpy, meaning “heat energy.” We call these events either endothermic (heat in) or exothermic (heat out) processes. The usual procedure to detect these heat events is by measuring the temperature change associated with the process. In this problem, you will dissolve several salts in water, measure the resulting temperature change, and then make deductions about the enthalpy of the process.

1. Start Virtual ChemLab and select Endothermic vs. Exothermic from the list of assignments. The lab will open in the Calorimetry laboratory.

2. There will be a bottle of sodium chloride (NaCl) on the lab bench. A weigh paper will be on the balance with approximately 2 g of NaCl on the paper.

3. The calorimeter will be on the lab bench and filled with 100 ml water. Click the Lab Book to open it.
Make certain the stirrer is On (you should be able to see the shaft rotating). In the thermometer window, click Save to begin recording data. Allow 20-30 seconds to obtain a baseline temperature of the water.

4. Drag the weigh paper with the sample to the calorimeter until it snaps into place and then pour the sample into the calorimeter. Observe the change in temperature until it reaches a maximum and then record data for an additional 20-30 seconds. Click Stop. (You can click on the clock on the wall labeled Accelerate to accelerate the time in the laboratory.) A blue data link will appear in the lab book. Click the data link and record the temperature before adding the NaCl and the highest or lowest temperature after adding the NaCl in the data table.

5. Click the red disposal bucket to clear the lab. Click on the Stockroom to enter. Click on the clipboard and select Preset Experiment #7 and repeat the experiment with NaNO3. Record the initial and final temperatures in the data table.

6. Click the red disposal bucket to clear the lab. Click on the Stockroom to enter. Click the clipboard and select Preset Experiment #8 and repeat the experiment with NaCH3COO (NaAc). Record the initial and final temperatures in the data table.

Data Table

Mixture T1 T2 DT (T2T1)
NaCl (s) + H2O (l)
NaNO3 (s) + H2O (l)
NaCH3COO + H2O (l)

Use your experimental data to answer the following questions.

7. Calculate ?T ( ?T = T2 – T1) for each mixture and record it in the data table.







67

Virtual ChemLab: General Chemistry Laboratories, Student Lab Manual/Workbook, v2.5, Third Edition, by Brian F. Woodfield, Matthew C. Asplund, and Steven Haderlie. Published by Prentice Hall. Copyright © 2006 by Pearson Education, Inc.



8. An exothermic process gives off heat (warms up). An endothermic process absorbs heat (cools off).
Which solutions are endothermic and which are exothermic? What is the sign of the change in enthalpy (DH) in each case?



9. Which solution(s) had little or no change in temperature?



5-1: Boyle’s Law: Pressure and Volume


Robert Boyle, a philosopher and theologian, studied the properties of gases in the 17th century. He noticed that gases behave similarly to springs; when compressed or expanded, they tend to “spring” back to their original volume. He published his findings in 1662 in a monograph entitled The Spring of the Air and Its Effects. In this experiment, you will make observations similar to those of Robert Boyle, and learn about the relationship between the pressure and volume of an ideal gas.

1. Start Virtual ChemLab and select Boyle’s Law: Pressure and Volume from the list of assignments.
The lab will open in the Gases laboratory.

2. Note that the balloon in the chamber is filled with 0.300 moles of an ideal gas (MW = 4 g/mol) at a temperature of 298 K, a pressure of 1.00 atm, and a volume of 7.336 L. To the left of the Pressure LCD controller is a lever that will decrease and increase the pressure as it is moved up or down; the digit changes depending on how far the lever is moved. Digits may also be clicked directly to type in the desired number. You may want to practice adjusting the lever so that you can decrease and increase the pressure accurately. Make sure the moles, temperature, and pressure are returned to their original values before proceeding.

3. Click on the Lab Book to open it. Back in the laboratory, click on the Save button to start recording P, V, T, and n data to the lab book. Increase the pressure from 1 atm to 10 atm one atmosphere at a time. Click Stop to stop recording data, and a blue data link will appear in the lab book. To help keep track of your data links, enter “Ideal Gas 1” next to the link.

4. Zoom Out by clicking the green arrow next to the Save button. Click Return Tank on the gas cylinder. On the table underneath the experimental chamber is a s
Submitted: 3 years ago.
Category: Homework
Expert:  Ryan replied 3 years ago.
Hi,

Thank you for requesting me. I do appreciate it.

It seems that part of your question was cut off as there appears to be information missing. You might need to put all of the text into a Word document and then upload it to a file sharing site such as mediafire.com or sendspace.com. You can then copy and paste the link to the file, which will allow me to access the file.

Thanks,

Ryan
Customer: replied 3 years ago.
So what has been posted is what I have. I can complete the virtual lab portion myself and resubmit so that you have all of the information you need. Thanks for your help.
Customer: replied 3 years ago.
Relist: I still need help.

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
< Last | Next >
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
  • He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here. Diane Dallas, TX
 
 
 

Meet The Experts:

 
 
 
  • Manal Elkhoshkhany

    Tutor

    Satisfied Customers:

    4520
    More than 5000 online tutoring sessions.
< Last | Next >
  • http://ww2.justanswer.com/uploads/BU/BusinessTutor/2012-2-2_115741_Kouki2.64x64.jpg Manal Elkhoshkhany's Avatar

    Manal Elkhoshkhany

    Tutor

    Satisfied Customers:

    4520
    More than 5000 online tutoring sessions.
  • http://ww2.justanswer.com/uploads/LI/lindaus/2012-6-10_04811_IMG20120609164157.64x64.jpg Linda_us's Avatar

    Linda_us

    Finance, Accounts & Homework Tutor

    Satisfied Customers:

    3121
    Post Graduate Diploma in Management (MBA)
  • http://ww2.justanswer.com/uploads/ComputersGuru/2010-02-13_051118_Photo41.JPG LogicPro's Avatar

    LogicPro

    Engineer

    Satisfied Customers:

    3035
    Expert in Java C++ C C# VB Javascript Design SQL HTML
  • http://ww2.justanswer.com/uploads/lanis/2009-4-1_233717_phput9xef_c1pm.jpg Lani S.'s Avatar

    Lani S.

    Tutor

    Satisfied Customers:

    2457
    Registered Nurse, Internet Researcher, Private Tutor
  • http://ww2.justanswer.com/uploads/chooser77/2009-08-18_162025_Chris.jpg Chris M.'s Avatar

    Chris M.

    M.S.W. Social Work

    Satisfied Customers:

    2341
    Master's Degree, strong math and writing skills, experience in one-on-one tutoring (college English)
  • http://ww2.justanswer.com/uploads/JawaadAhmed/2009-6-27_12137_SIs_SHadi.jpg F. Naz's Avatar

    F. Naz

    Chartered Accountant

    Satisfied Customers:

    1975
    Experience with chartered accountancy
  • http://ww2.justanswer.com/uploads/JK/jkcpa/2011-1-16_182614_jkcpa.64x64.jpg Bizhelp's Avatar

    Bizhelp

    CPA

    Satisfied Customers:

    1873
    Bachelors Degree and CPA with Accounting work experience