Adila's Workshop Week 4 Topic is endorsed

[Chem_Mod]

Hey everyone!

Here's the worksheet and summary sheet for this Wednesday's sessions! Like last week, you don't have to have the worksheets completed before the sessions since we'll be going over them together. Make sure to note that I did change one of my session times so my 9am session has been moved to 3pm on Wednesdays at the same zoom link! Feel free to email me any questions at adilaahmed02@gmail.com

Hope to see you there!

[Chem_Mod]

Hi everyone! Thank you to everyone who came to my 11am session and I hope it was helpful! I'm sorry for the late notice but I wasn't feeling too good during that session and the feeling has gotten worse over the last couple hours so I will not be hosting my 3pm session today. I will still upload the answer key and if you have any questions, feel free to email me!

[AnoushkaBhat2J]

Hi Adila! In Worksheet 4 Question 4, what is the logic behind the first method of solving the problem? I'm getting a bit confused how the final temperature of the zinc was put at the end, since I thought delta t was supposed to be final minus initial. Also, for #2, if the energy gained by water is equal to the energy lost by the metal, why is there not a negative sign used?

[Chem_Mod]

Hi Adila! In Worksheet 4 Question 4, what is the logic behind the first method of solving the problem? I'm getting a bit confused how the final temperature of the zinc was put at the end, since I thought delta t was supposed to be final minus initial. Also, for #2, if the energy gained by water is equal to the energy lost by the metal, why is there not a negative sign used?

The way I do specific heat tends to be the unconventional way bedcause I don't like to deal with additional minus signs. Basically, the minus sign that's usually associated with the loss of energy is incorporated into the change in temperature.

So, you usually have this: mC(Tf-Ti) = -mC(Tf-Ti). If you were to kind of distribute that negative sign into the delta T expression you would be left with mC(Tf-Ti) = mC(Ti-Tf). I like to have my changes in temperature be T(large value) - T(small value) so I don't have any negative values. The idea behind this is that if water is heated up then the energy needed to heat it up must come from somewhere, and since we know that it is coming from the zinc then that means the zinc must have decreased in temperature so the final temperature is lower than its inital temperature.

If you are not comfortable with this way, then do it the other way since you are more susceptible to making mistakes if you use a method you do not understand.

The same idea is applied to question 2 where I just distributed the negative sign into the delta T expression. The water is heated up by the energy that is lost by the metal so that means that the metal went from a higher temperature to a lower temperature and the water went from a lower temperature to a higher temperature. This can be seen by the equilibrium temperature being in between the initial temperatures of the water and the metal.