Question

Physics: I am not sure about the math part in here.

Answer 1

Scientists at UC Davis discovered two new substances Aggieum (Ai) and Cyclerium (Cy). In an experiment the scientists place 1kg of Aggieum initially at 100°C with Cyclerium initially at 310°C in an insulated container. Once the two substances come to thermal equilibrium, the scientists observe that 0.5 kg of Cyclerium has frozen, and it is in the mixed solid/liquid phase. (Constants for the two substances are given above.)

1) Depict the process using an energy-interaction diagram. Briefly explain how you determined the final temperature.

Answer 2

Phase change for Cy, Thermal energy change for Ai. Total energy is zero because everything is in a insulated container (closed system).

Answer 3

ΔEth=Thermal energy ; ΔEB=Phase change energy

Equations:
ΔEth=mcΔT; ΔEB=±|ΔmΔH|
Constants:
Aggieum: TMP = 1500°C, c=2 kJ/kgK, ΔHmelt = 350 kJ/kg.
Cyclerium: TMP = 300°C, TBP = 2000°C, c=5 kJ/kgK, ΔHmelt = 100 kJ/kg|

Answer 4

mcΔT+ΔmΔH=0
(1kg*2 kJ/kgK(Tf-100*C))+(0.5kg)(100 kJ/kg)=0

Can Δm for Cy be 0.5kg (the frozen part)?

Answer 5

Δm for Cy = 0.5 kg only for latent heat which i assume is represented as ΔH

mcΔT would only apply for heating and cooling of the same phase

Answer 6

Alright.Thanks!

Answer 7

the super nice thing about phase change is that they occur at the same temperature during the process