Final Fantasy V introduces several new job classes seen in later titles. One such ability is the Chemist/Mixer. In Final Fantasy X, Rikku was able to mix items in battle for unique effects, and in X-2 there was a Chemist job class.
Chemists have the ability to take two items, and make something new with them. Without knowing the effects of the combinations, you might mix something that you did not want.
Below is a table showing the combined items, and also a table, showing their effects. (And don't worry about doing it right the first time. There is no teacher grading you on this.)

ITEM	Potion	Ether	Antidote	Maiden's Kiss	Hi-Potion	Turtle Shell
Potion	Potion	X-Potion	Neutrilizer	Maiden's Kiss	Life Water	Ether 2
Ether	X-Potion	Ether	Resist Poison	Lilith Kiss	Balm of Gilead	X-Potion
Antidote	Neutrilizer	Resist Poison	Antidote	Levisalve	Neutrilizer	Turtle Soup
Maiden's Kiss	Maiden's Kiss	Lilith Kiss	Levisalve	Maiden's Kiss	Maiden's Kiss	Succubus Kiss
Hi-Potion	Life Water	Balm of Gilead	Neutrilizer	Maiden's Kiss	Hi-Potion	Triple Ether
Turtle Shell	Ether 2	X-Potion	Turtle Soup	Succubus Kiss	Triple Ether	Protect Potion
Dark Matter	Devil's Juice	Dark Ether	Poison	Toad Kiss	Devil's Juice	TNT
Dragon Fang	Dragon Power	Dragon Shielding	Poison Breath	Dragon Kiss	Dragon Power	Dud Potion
Eye Drops	Eye drop+	Resist Fire	Smelling Salts	Lamia's Kiss	Eye Drop	Hasty-aid
Elixir	Elixir	Elixir	Elixir	Lilith Kiss	Elixir	Dud Potion
Phoenix Down	Resurection	Reincarnate	Resist Ice	Kiss of Life	Resurection	Remedy
Holy Water	Potion	Ether	Samson's Might	Blessed Kiss	Hi-Potion	Bacchus Cider

ITEM	Dark Matter	Dragon fang	Eye Drop	Elixir	Phoenix Down	Holy Water
Potion	Devil's Juice	Dragon Power	Eye Drop+	Elixir	Resurection	Potion
Ether	Dark Ether	Dragon Shielding	Resist Fire	Elixir	Reincarnate	Ether
Antidote	Poison	Poison Breath	Smelling Salts	Elixir	Resist Ice	Samson's Might
Maiden's Kiss	Toad Kiss	Dragon Kiss	Lamia's Kiss	Kiss of Life	Life Kiss	Blessed Kiss
Hi-Potion	Devil's Juice	Dragon Power	Eye Drop			Hi-Potion
Turtle Shell	TNT	Dud Potion	Haste-aid			Bacchus Cider
Dark Matter	Shadow Flare	Dark Breath				Dud Potion 2
Dragon Fang	Dark Breath	Dragon Breath				Holy Breath
Eye Drops	Dark Gas	Dark Sigh				Elemental Power
Elixir	Dark Elixir	Goliath Tonic				Elixir
Phoenix Down	Death Potion	Dragon Defense	Resist Thunder	Reincarnate	Phoenix Down	Life Shield
Holy Water	Dud Potion 2	Holy Breath	Elemental Power	Elixir	Life Shield	Holy Water

New Item	Description	New Item	Description
Potion	Restores HP	Hi-Potion	Restores HP
Ether	Restores MP	Maiden's Kiss	Cures Toad, and restores HP
Dud Potion	Casts Time Slip	Life Water	Casts Regen
X-Potion	Fully restores HP	Resurection	Revives fallen ally
Neutrilizer	Cures Poison, and restores HP	Eye Drop	Cures Blind
Dragon Power	Raise level 20 Pts	Devil's Juice	Causes 666 HP damage
X-Potion	Fully restores HP	Ether 2	Triple the power of Ether
Reincarnate	Revive fallen ally with full HP	Lilith Kiss	Drains targets MP
Resist Poison	Resistance to Poison	Resist Fire	Resistance to fire
Dragon Shielding	Resistance to fire, ice, and lightning	Dark Ether	Drains 3/4 of targets MP
Goliath Tonic	Doubles max HP	Dark Elixir	Reduces HP/MP to single didgets
Life Kiss	Raise KO ally with 1/2 HP & full MP	Life Shield	Resistance to sudden death attacks
Remedy	Cures all status effects	Resist Ice	Resistance to ice
Resist Thunder	Resistance to lightning	Dragon Defense	Increases phys and mag defense
Death Potion	Casts Doom	Blessed Kiss	Casts Berserk, Haste, and Image
Succubus Kiss	Drains HP from target	Levisalve	Casts Float on target
Lamia's Kiss	Confuses enemy	Toad Kiss	Casts Toad
Bacchus Cider	Casts Berserk	Samson's Might	Raises level 10 Pts
Elemental Power	Raises magical damage 50%	Holy Breath	Casts Holy Wind
Protect Potion	Casts Safe	Turtle Soup	Decreases def/mdef by 1/2
Haste-aid	Casts Haste	TNT	Fire damage at the cost of users life
Smelling Slats	Cures all status for rest of the fight	Poison Breath	Poisons all enemies
Poison	Poisons target	Dark Sigh	Blinds and confuses target
Dark Gas	Blinds Target	Dragon Breath	Fire, ice, and lightning damage
Dark Breath	Unholy fire damage	Shadow Flare	Shadow damage
Holy Water	Cures Zombie, and restores HP