q_system + q_surroundings = 0

[Sasha Gladkikh 2A]

What is the concept behind the equation q_system + q_surroundings = 0? Is this equation only applicable for reactions that occur in calorimeters? And if so, why?

[Meghan Spoeri 2D]

Hi! If you were to set them equal to each other, you would get q system = -q surroundings. This means that the heat lost by a system is gained by the surroundings and vice versa. In other words, the total energy remains constant in interactions between a system and its surroundings. I'm not sure about whether this applies to reactions in a calorimeter or not, however.

[Brynn 2F]

Calorimeters measure energy transferred as heat. Heat lost by a reaction is gained by a calorimeter. I believe this also applies when a calorimeter is not being used. In that case it's simply the environment or surroundings that is gaining the energy.

[Kayla Tran 3C]

q_system + q_surroundings = 0 because heat is being exchanged between the two, so they are equal and opposite in sign. I think it is still applicable without calorimeters.

[Emily Engelkemier 1E]

Any heat that is lost by the system is gained by the surroundings (equal and opposite in sign), and any heat gained by the system is lost by the surroundings.

[William Huang 1K]

This kind of ties into the conservation of energy, where energy cannot be created nor destroyed, because energy (lets say in the form of heat) being released by a system is absorbed by the surroundings; absorbing energy is positive and losing energy is negative, so if an equal amount of energy is lost and gained by the system and the surroundings respectively, the sum of those 2 numbers is 0.

[405669838]

Hi! I believe this is because q is the change in heat. If the system I staining heat, it is going it from the surroundings, so the surrounding change in heat is that same amount, but negative (and the vice versa is true). Therefore, when added together the product should be 0.