Negative sign in q_sys=q_surr

[Jamie Lin 1K]

In which situations would the transfer of heat be -q_sys = q_surr? In which situations would the transfer of heat be q_sys = -q_surr?

[Noah Ho 1F]

When delta H is negative, q_sys would be negative since it's releasing energy and q_surr would gain energy. When delta H is positive, q_sys would be positive and q_surr would lose energy.

[Misha_Khan_2H]

q_system = - q_surroundings as heat/energy lost by the system will be gained by the surroundings and vice versa.
When the system is losing heat, then q_system is negative and q_surroundings is positive.
When the system is gaining heat or energy, then q_system is positive and q_surroundings is negative.

[Ashley Hiti 1K]

Something else to consider is that q_sys + q_surr = 0

[Jelix Tsan 2H]

Saying that -q_sys = q_surr is the same as saying q_sys = -q_surr. This equation is used when the system transfers heat energy to the surrounding, or vice versa.

[Dillon Taing 3H]

The negative sign is assigned depending on which way heat energy is being transferred between the system and its environment. When the system releases heat energy and the enthalpy is negative, then q_sys is negative. Similarly, when heat energy is moved from the surroundings to the system and the enthalpy value is positive, then q_surr is negative.