Appaulingly
Appaulingly t1_j6ygnxs wrote
Reply to comment by haysoos2 in What are the effects of adding rock salt to a cooler full of ice? by Ok_Kareem_7223
When you add salt to ice+water the temperature decreases. Your misconception is that somehow energy is being removed from the system.
Appaulingly t1_j6ycp2e wrote
Reply to comment by haysoos2 in What are the effects of adding rock salt to a cooler full of ice? by Ok_Kareem_7223
This is not true. You can do the kitchen experiment yourself.
Appaulingly t1_j6y9olg wrote
Reply to comment by parrotwouldntvoom in What are the effects of adding rock salt to a cooler full of ice? by Ok_Kareem_7223
No the melting is endothermic.
>just adding salt can't take energy out of the system
The temperature decreasing does not mean that the total energy of the system has changed. There is an energy transfer between kinetic energy and potential within the system.
Only really in an ideal gas system does the temperature relate to the total energy.
Appaulingly t1_j6y813l wrote
Reply to comment by haysoos2 in What are the effects of adding rock salt to a cooler full of ice? by Ok_Kareem_7223
Energy is conserved. The thermal, kinetic energy of the ice and water is transferred to the potential energy in the bonds of the ice (to break them).
The temperature of a system is only ever directly related to the total energy of a system for an ideal gas.
Appaulingly t1_j6u8o9s wrote
Ice in equilibrium with (pure) water will stay at 0 degrees C. No higher and no lower. If you add salt to the water, the equilibrium temperature will decrease. So a brine ice mixture can be lowered below 0 degrees C. This lower temperature system would "stay cool longer" because it is colder.
>It's as if they're saying that by adding salt, they've removed even more energy (heat) from the mass
Melting is an endothermic process. This process will "remove" heat via bond breaking in the ice. So by adding salt to the water and lowering the equilibrium temperature, the system will respond by melting some of the ice. This consumes energy and lowers the temperature until equilibrium temperature is reached.
EDIT: To clarify a misconception, an observed decrease in temperature does not equate to the "removal of energy from the system" (when simply adding salt). A decrease in temperature can occur when there is a transfer of kinetic energy to potential (when ice melts endothermically). Regardless, in the water-ice system the temperature is not actually proportional to kinetic energy. That is only the case in an ideal gas.
Appaulingly t1_j5ojqgw wrote
Reply to Why does hot air cool? by AspGuy25
Thermal cameras aren't that great at accurately measuring temperature particularly when comparing different materials. The emissivity of the metal with be very different to that of the other materials and so a different temperature will be measured.
Appaulingly t1_iwozvhz wrote
Reply to If energy levels in quantum systems are quantized, where does the excess energy go? by Least_Ad104
If a bound electron is photoemitted the “extra” energy becomes the energy of the free electron. Free particles don’t have quantised states.
Appaulingly t1_j6yujev wrote
Reply to comment by haysoos2 in What are the effects of adding rock salt to a cooler full of ice? by Ok_Kareem_7223
If you had water that was for example at 105C, you're stating it would stay at 105C as it boils? And that the boiling would not lead to a decrease in the temperature?