Find the equilibrium temperature & the amount of ice/water

In summary, there was a conversation where the speaker was stuck on a question and asked for help. The other person pointed out that an important part of the question was not explained in the attempt, leading to guesswork in the solution. They also advised against posting images and emphasized typing out the work. The question asked for the reasoning behind a specific equation, and the conversation ended with the speaker being asked about their calculation's results.
  • #1
jpastones
1
0
Homework Statement
In an insulated vessel, 600g of ice at -20C is added to 250g of water at 18C.
Cice= 0.5 cal/gC, Cwater= 1 cal/gC. Lfusion= 80 cal/g.
Find the equilibrium temp of the system. Explain the reasons.
At the equilibrium temp, will the system be all water, all ice, or a mixture of both? Give the amounts of water and/or ice in the system at equilibrium.
Relevant Equations
Q=m*c*(Tf-Ti)
Q=m*Lfusion

Qsystem=0
Qsystem= Qice + Qwater
m*c*(Tf-Ti)ice + m*c*(Tf-Ti)water = 0
242492


That's how far I've gotten and now I'm stuck!
 
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  • #2
A very important part of the question is "Explain the reasons." In your attempt you have not done that and so following your solution is a bit of guesswork. For example, when you write
$$
m_{\rm ice} c_{\rm ice}\Delta T_{\rm ice} + m_{\rm water} c_{\rm water} \Delta T_{\rm water} = 0
$$
(do not forget the subscripts!), what is your reasoning behind this?

Also, in the future, do not post images of your work. Type it out! As per forum policy.
 
  • #3
The three possibilities at the final state are: (1) all liquid water above 0 C (2) all ice below 0 C or (3) a combination of liquid water and ice at 0 C. What do you think your calculation has shown so far?
 

Related to Find the equilibrium temperature & the amount of ice/water

1. How do you calculate the equilibrium temperature?

The equilibrium temperature can be calculated by using the formula: T = (m1 * T1 + m2 * T2) / (m1 + m2), where m1 and m2 are the masses of the ice and water respectively, and T1 and T2 are their respective temperatures.

2. How do you determine the amount of ice and water at equilibrium?

The amount of ice and water at equilibrium can be determined by using the formula: m1 / m2 = (T2 - Teq) / (Teq - T1), where Teq is the equilibrium temperature calculated in the previous step. This will give you the ratio of the masses of ice and water at equilibrium.

3. What factors affect the equilibrium temperature?

The factors that affect the equilibrium temperature include the masses of the ice and water, their respective temperatures, and the specific heat capacities of ice and water. Other factors such as atmospheric pressure and external heat sources can also play a role.

4. How does the equilibrium temperature change if the mass of ice is increased?

If the mass of ice is increased, the equilibrium temperature will decrease. This is because the larger mass of ice will require more energy to melt, causing the overall temperature to decrease until the system reaches equilibrium.

5. What is the significance of finding the equilibrium temperature and amount of ice/water?

Finding the equilibrium temperature and amount of ice/water is important in understanding the behavior of substances at different temperatures and how they reach a state of equilibrium. This knowledge can also be applied in various scientific fields such as thermodynamics, chemistry, and climate science.

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