Finding the final temperature of a final solution. putting ice in soda/water

AI Thread Summary
The discussion revolves around calculating the final temperature of a soda solution after adding ice. The initial temperature of the soda is 22°C, and 125 g of ice at -25°C is added. The heat gained by the ice during melting and warming is balanced against the heat lost by the soda. The initial calculations provided were incorrect due to unit conversion errors and sign issues. Ultimately, the correct approach involves ensuring all units are consistent and accounting for the phase change of ice to water.
apbuiii
Messages
14
Reaction score
0

Homework Statement


Suppose you have a 24 ounce mug of soda (treat as water) at room temperature, which is 22 C. Warm soda tastes bad, so you add 125 g of ice at -25 C to the soda. What is the temperature (in C) of the soda once all the ice melts and the solution reaches a uniform temperature? The heat of fusion is 6.01 kJ/mol and the heat of vaporization is 40.7 kJ/mol. The specific heat capacity of ice and water are 2.09 and 4.18 J/g-K, respectively. Assume no heat is transferred to the soda from the surroundings.


Homework Equations


q= (mass)(Specific heat)(change in temp); q=(moles)(delta-enthalpy)


The Attempt at a Solution


So I did q(soda lost)= q(ice gained). I found the q of the ice by (125g)(0--25)(2.09) + (125g)(1mol/18g)(6.01 KJ/mol)(1000J/KJ)= 48087.35 J. So now I set it equal to the q(soda). I had 24 oz of soda which is 681 grams: 48087.35= (681g)(4.18)(TempFinal-22). But then I get 39 C which is wrong I'd assume! Please help me by showing all the steps. Thanks!
 
Physics news on Phys.org
In general you are on the right track. Pay attention to signs, my bet is that that's where you got lost.
 
You should convert all units to calories and grams here;
specific heat of water = 1 cal/gram deg C
specific heat ice = .5 cal/gram deg C
latent heat of fusion ice = 80 cal/gram
Now take the 681 grams of soda from 22 deg C to 0 deg C and obtain 14982
calories
The 125 grams of ice will absorb 1562 calories going from -25 C to
0 C and will absorb 10000 cal melting
So now you have 806 grams of water at 0 deg C and 3420 calories.
Therefore 3420 calories = (Temp) ( 806 grams)
 
Last edited:
morrobay said:
You should convert all units to calories and grams here

There is no need for that. cal is a nice unit when working with water, but it loses its simplicity when you have a system in which water changes state of matter.
 
Yeah, thanks guys. I ended up figuring it out :)
 
Thread 'Confusion regarding a chemical kinetics problem'
TL;DR Summary: cannot find out error in solution proposed. [![question with rate laws][1]][1] Now the rate law for the reaction (i.e reaction rate) can be written as: $$ R= k[N_2O_5] $$ my main question is, WHAT is this reaction equal to? what I mean here is, whether $$k[N_2O_5]= -d[N_2O_5]/dt$$ or is it $$k[N_2O_5]= -1/2 \frac{d}{dt} [N_2O_5] $$ ? The latter seems to be more apt, as the reaction rate must be -1/2 (disappearance rate of N2O5), which adheres to the stoichiometry of the...
I don't get how to argue it. i can prove: evolution is the ability to adapt, whether it's progression or regression from some point of view, so if evolution is not constant then animal generations couldn`t stay alive for a big amount of time because when climate is changing this generations die. but they dont. so evolution is constant. but its not an argument, right? how to fing arguments when i only prove it.. analytically, i guess it called that (this is indirectly related to biology, im...
Back
Top