Clarifying question about internal energy and heat
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Clarifying question about internal energy and heat
In the textbook, it says if energy enters a system as heat the internal energy of the system increases and if it leaves a system as heat then the internal energy of the system decreases. Does this mean that exothermic reactions which produce heat as a product always have a lower internal energy than an endothermic reaction that requires an input of heat?
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Re: Clarifying question about internal energy and heat
I don't think it necessarily means this. It depends on how much energy is lost or gained through the course of the reaction and the starting energy of the system as well. Maybe it happens more often, but I don't that this has to be the case.
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Re: Clarifying question about internal energy and heat
The textbook is explaining that if you add heat to a system, that system will have a higher amount of energy than it used to, and vice versa. For example, if you heat a beaker, that system has an increase in internal energy, because there is now more energy available within the beaker. An exothermic reaction will only lower the internal energy if the heat it gives off leaves the system, which would happen if you have an open system. However, if you have an isolated system, there won't be any change in the internal energy because the heat given off cannot transfer to the surroundings. Exothermic reactions might not always have a lower internal energy than endothermic reactions because of system type and the different energy needs of different reactions.
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