-8.2 J
Delta E = q + w
Delta E = 12.4 J + -4.2J
Delta E = -8.2
It is negative because it is an exothermic reaction, hence "work on the surroundings"
An isolated system is a system that doesn't not interact with its surroundings. No interactions at all. No work, no heat transfer. An adiabatic system is one that does not permit heat transfer between the system and its surroundings. It can do work on the surroundings.
An exothermic reaction releases heat energy to the surroundings, so it is not considered dissipated energy. Instead, it is a form of energy transfer from the system to the surroundings. Dissipated energy refers to energy that is lost as heat and cannot be used to do work.
The surroundings do 4.20 x 10^3 J of work on the system, as work done by the surroundings is considered positive. The change in internal energy of the system is 196 kJ - 4.20 kJ = 191.8 kJ. This change includes the energy flow as heat and work.
The change in internal energy is the sum of heat added to the system and work done by the system on the surroundings. So, the change in internal energy is 2.500J (heat absorbed) - 7.655J (work done), resulting in a change of -5.155J.
-70 Joules
There are two ways that a substance ( called the System ) may release energy to the Surroundings :( 1 ) Heat may be released by heat transfer from the System to the Surroundings. Heat transfer from the System to the Surroundings requires the System temperature to exceed the temperature of the Surroundings and the presence of one or more heat transfer modes ( conduction, convection, and/or radiation.( 2 ) Work done by the System of on the Surroundings corresponding to a force moving through a distance, such as when the substance expands. Substance confined to a cylinder with a piston may expand, doing work on the Surroundings.
In this scenario, the gas is doing work on its surroundings, so the work is negative. Since heat is being released from the gas to its surroundings, the heat is also negative. The sign convention typically defines work done by the system as negative and heat released from the system as negative.
Positive work done on the surroundings by the system (q>0) and negative heat transferred from the system to the surroundings (w<0).
An isolated system is a system that doesn't not interact with its surroundings. No interactions at all. No work, no heat transfer. An adiabatic system is one that does not permit heat transfer between the system and its surroundings. It can do work on the surroundings.
An exothermic reaction releases heat energy to the surroundings, so it is not considered dissipated energy. Instead, it is a form of energy transfer from the system to the surroundings. Dissipated energy refers to energy that is lost as heat and cannot be used to do work.
A system that does no work but receives heat from the surroundings is referred to as a heat engine. This is because even though the system is not performing any mechanical work, it is still able to convert some of the heat energy it receives into other forms of energy, such as thermal energy.
The surroundings do 4.20 x 10^3 J of work on the system, as work done by the surroundings is considered positive. The change in internal energy of the system is 196 kJ - 4.20 kJ = 191.8 kJ. This change includes the energy flow as heat and work.
The change in internal energy is the sum of heat added to the system and work done by the system on the surroundings. So, the change in internal energy is 2.500J (heat absorbed) - 7.655J (work done), resulting in a change of -5.155J.
In an adiabatic experiment, the system is isolated from its surroundings, so there is no heat exchange with the surroundings. The decrease in internal energy of the system is equal to the work done on the system. This relationship can be expressed by the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system.
Δ E = -196 kj + 420 kJ = 224 kJ
the system gains heat and does work on the surroundings
-70 Joules