system
Given the following post, respond as if you're commenting on Reddit:
human
[alchemy] if we were to combine fire and electricity, what would it make?
gpt
Depends on the practice of Alchemy to which you are referring. Even more importantly, it depends on what you mean by combining fire and electricity.

Alchemy is a broad term that covers a wide array of practices that are usually some combination of magical, physical, and spiritual.

Chemistry is the most common form of Alchemy available to the masses and is completely physical. In this particular practice of Alchemy there are many ways to achieve the effect of combining fire and electricity. Looking at one: what happens when you burn a lithium battery. For starters, the electrical source is consumed by the fire, makin the fire temporarily more powerful until the electrical source is depleted. This is accompanied by an explosion and the release of toxic fumes.

There are, like all alchemic practices, many other ways to combine fire and electricity in this practice. C4 with a remote trigger is an obvious example with obvious uses. Engines are a less thought of example that uses both fire and electricity. Gas stoves, electric fireplaces, the list goes on.

 A more magical form of Alchemy is potion making. Because of the nature of magic and spirit these two are often interlinked to some degree, but we will look at as simple a magical process as we can. The combination of a phoenix feather and a thunderbird feather in a simple base mixture has different results depending on the base mixture used and the incantation, ritual, or rite performed around it. 

A wizard in his tower carefully mixing them in beakers and flasks is likely going to create a potion of energy which can then be further diluted and condensed into a power stone which they can use as an energy source (both animals naturally produce their element endlessly) to help empower their magic. A witch hapazardly mixing them into a cauldron on the summer solstice is more likely to be interested in the fumes the potion is releasing, letting them spread over the countryside to cause the air (she's using bird feathers after all) to become dry and filled with electricity, setting the perfect curse of a drought and eventual lightning fire on the valley.

The results of course change when different elements of the process are changed. Changing the phoenix feather to brimstone will cause the witches brew to become heavier and seep into the ground cursing the crops instead of the air. Changing the thunderbird feather to the white fur of the raiju causes the wizards potion to become less stable (the phoenix must die and be reborn and the raiju becomes active during thunderstorms). Because of this it can no longer be diluted and condensed into a consistent power stone, however, it can be thrown and explode into alchemical fire, unquenchable and unstoppable once activated.

And finally, the spiritual. This is less about the physical objects used and more about the process and end result. Because of the more esoteric nature it can be hard to label this form of Alchemy but it is often used by shamans and spiritualists. 

A spiritualist might daily drink the tea from a tree struck by lightning. There is no real 'effect' that a potion maker would see but the spiritualist knows better. There are no changes on the first day, or the second, the third, or the fourth. It is only after a year of drinking the tea that any effects begin to show. By daily inviting the spirits of fire and lightning into their life the spiritualist has begun to surround themselves by minor spirits which slightly change the world around them. Fire might burn just a little hotter, a little longer. Lightning might strike a little more often. These aren't big changes, the spiritualist isn't interested in flashy shows like the potion makers. They simply like the spirits of fire and lightning and want to invite it into their lives. This in turn, will cause the spirits of fire and lightning to like the individual. It will take a lifetime before the effects are noticable, before major spirits decide to hang around. The spiritualist's fires will never go out unless they want them to. Rain and lightning will come almost daily. The old spiritualist, cozy by their fire, never feeling too hot or too cold, will smile as the storm rages outside and they cuddle in their rocker reading a book and sipping their tea.

Shamans, on the other hand, take more direct control over the spirits. They summon sprits of fire and lightning and shove them into a vessel, creating an elemental. Similar to the wizard the shaman may use this elemental as a power source, giving strength to their other magical pursuits. Or like the witch they may release them as a curse to plague the valley with drought and lightning fires. Or they may keep them by their side as a fire/lightning elemental to burn or shock their foes.

This doesn't even showcase half the ways the different practices of alchemy can combine fire and lightning. Practices that combine the physical and spiritual might deal with shoving spirits into a host giving them powers over both elements. Different components, different rituals, different power sources all play a part in the end result.