Added this mod to github

core.lua

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+input={}
+out1 = {}
+out2 = {}
+out3 = {}
+out4 = {}
+out5 = {}
+out6 = {}
+out7 = {}
+out8 = {}
+out9 = {}
+count=0
+minetest.register_craftitem("chemistry:reactor",
+{
+  description = "Chemical reactor",
+  inventory_image = "reactor.png",
+})
+minetest.register_craft({
+	output = "chemistry:reactor",
+	recipe = {
+		{"default:steel_ingot", "default:steel_ingot", "default:steel_ingot"},
+		{"default:steel_ingot", "default:chest", "default:steel_ingot"},
+		{"default:steel_ingot", "default:steel_ingot", "default:steel_ingot"}
+	}
+})
+function register_chemical_recepie(from,to1,to2,to3,to4,to5,to6,to7,to8,to9)
+		table.insert(input, from)
+		table.insert(out1, to1)
+		table.insert(out2, to2)
+		table.insert(out3, to3)
+		table.insert(out4, to4)
+		table.insert(out5, to5)
+		table.insert(out6, to6)
+		table.insert(out7, to7)
+		table.insert(out8, to8)
+		table.insert(out9, to9)
+		count=count+1
+end
+for index = 1, #input do
+minetest.register_craft({
+	output = input[index],
+	recipe = {
+		{out1[index], out2[index], out3[index]},
+		{out4[index], out5[index], out6[index]},
+		{out7[index], out8[index], out9[index]}
+	},
+})
+end
+formspec= "size[10,10]"..
+		  "list[current_name;from;4,0;1,1;]"..
+		  "list[current_name;result;3,2;3,3;]"..
+		  "listring[current_name;result]"..
+		  "listring[current_player;main]"..
+		  "listring[current_name;from]"..
+		  "list[current_player;main;1,6;8,4;]"
+function where(it,arr)
+for index=1,count do
+if arr[index]==it then
+return index
+end
+end
+end
+function react(pos, listname)
+	if listname=="from" then
+	local meta=minetest.get_meta(pos)
+	local inv = minetest.get_inventory({type="node", pos=pos})
+	if inv:is_empty("result") then
+	if not inv:is_empty("from") then
+	local from = inv:get_stack("from", 1)
+		if from:get_count()>0 and from:get_count()<100 then
+			numx = from:get_count()
+		local name=from:get_name()
+		local num=where(name,input)
+	 if num ~=nil then
+	 local to1 = inv:get_stack("result", 1)
+	 local to2 = inv:get_stack("result", 2)
+	 local to3 = inv:get_stack("result", 3)
+	 local to4 = inv:get_stack("result", 4)
+	 local to5 = inv:get_stack("result", 5)
+	 local to6 = inv:get_stack("result", 6)
+	 local to7 = inv:get_stack("result", 7)
+	 local to8 = inv:get_stack("result", 8)
+	 local to9 = inv:get_stack("result", 9)
+	 local item1=out1[num]
+	 local item2=out2[num]
+	 local item3=out3[num]
+	 local item4=out4[num]
+	 local item5=out5[num]
+	 local item6=out6[num]
+	 local item7=out7[num]
+	 local item8=out8[num]
+	 local item9=out9[num]
+	 stack1={name=item1,count=numx}
+	 stack2={name=item2,count=numx}
+	 stack3={name=item3,count=numx}
+	 stack4={name=item4,count=numx}
+	 stack5={name=item5,count=numx}
+	 stack6={name=item6,count=numx}
+	 stack7={name=item7,count=numx}
+	 stack8={name=item8,count=numx}
+	 stack9={name=item9,count=numx}
+	 inv:set_stack("result", 1, stack1)
+	 inv:set_stack("result", 2, stack2)
+	 inv:set_stack("result", 3, stack3)
+	 inv:set_stack("result", 4, stack4)
+	 inv:set_stack("result", 5, stack5)
+	 inv:set_stack("result", 6, stack6)
+	 inv:set_stack("result", 7, stack7)
+	 inv:set_stack("result", 8, stack8)
+	 inv:set_stack("result", 9, stack9)
+	 inv:set_stack("from", 1, {})
+minetest.log("action","pass")
+end
+minetest.log("action","pass")
+end
+minetest.log("action","pass")
+end
+minetest.log("action","pass")
+end
+minetest.log("action","pass")
+end
+end
+function retry(pos, listname)
+if listname=="result" then
+react(pos, "from")
+end
+end
+function testit(pos)
+	local inv = minetest.get_inventory({type="node", pos=pos})
+	if inv:is_empty("result") and inv:is_empty("from") then
+	return true
+	end
+	return false
+end
+minetest.register_node("chemistry:reactor",
+{
+  description = "Chemical reactor",
+  tiles = {"reactor.png"},
+  on_metadata_inventory_put = react,
+  on_metadata_inventory_take = retry,
+  groups = {cracky=2},
+  can_dig = testit,
+})
+minetest.register_abm({
+	nodenames = {"chemistry:reactor"},
+	interval = 1,
+	chance = 1,
+	action = function(pos, node, active_object_count, active_object_count_wider)
+		local meta=minetest.get_meta(pos)
+		local inv = minetest.get_inventory({type="node", pos=pos})
+		meta:set_string("formspec",formspec)
+		if inv~=nil then
+		inv:set_size("from", 1)
+		inv:set_size("result", 9)
+			react(pos,"from")
+		end
+	end,
+})
+hopper:add_container({
+	{"top", "chemistry:reactor", "result"}, -- take cooked items from above into hopper below
+	{"bottom", "chemistry:reactor", "from"}, -- insert items below to be cooked from hopper above
+})
+minetest.log("action","Chemistry!")

elements.lua

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+prvky={"H","He","Li","Be","B","C","N","O","F","Ne","Na","Mg","Al","Si","P","S","Cl","Ar","K","Ca","Sc","Ti","V","Cr","Mn","Fe","Co","Ni","Cu","Zn","Ga","Ge","As","Se","Br","Kr","Rb","Sr","Y","Zr","Nb","Mo","Tc","Ru","Rh","Pd","Ag","Cd","In","Sn","Sb","Te","I","Xe","Cs","Ba","La","Ce","Pr","Nd","Pm","Sm","Eu","Gd","Tb","Dy","Ho","Er","Tm","Yb","Lu","Hf","Ta","W","Re","Os","Ir","Pt","Au","Hg","Tl","Pb","Bi","Po","At","Rn","Fr","Ra","Ac","Th","Pa","U","Np","Pu","Am","Cm","Bk","Cf","Es","Fm","Md","No","Lr","Rf","Db","Sg","Bh","Hs","Mt","Ds","Rg","Cn","Nh","Fl","Mc","Lv","Ts","Og"}
+nazvy={"Hydrogen","Helium","Lithium","Beryllium","Boron","Carbon","Nitrogen","Oxygen","Fluorine","Neon","Sodium","Magnesium","Aluminum","Silicon","Phosphorus","Sulfur","Chlorine","Argon","Potassium","Calcium","Scandium","Titanium","Vanadium","Chromium","Manganese","Iron","Cobalt","Nickel","Copper","Zinc","Gallium","Germanium","Arsenic","Selenium","Bromine","Krypton","Rubidium","Strontium","Yttrium","Zirconium","Niobium","Molybdenum","Technetium","Ruthenium","Rhodium","Palladium","Silver","Cadmium","Indium","Tin","Antimony","Tellurium","Iodine","Xenon","Cesium","Barium","Lanthanum","Cerium","Praseodymium","Neodymium","Promethium","Samarium","Europium","Gadolinium","Terbium","Dysprosium","Holmium","Erbium","Thulium","Ytterbium","Lutetium","Hafnium","Tantalum","Tungsten","Rhenium","Osmium","Iridium","Platinum","Gold","Mercury","Thallium","Lead","Bismuth","Polonium","Astatine","Radon","Francium","Radium","Actinium","Thorium","Protactinium","Uranium","Neptunium","Plutonium","Americium","Curium","Berkelium","Californium","Einsteinium","Fermium","Mendelevium","Nobelium","Lawrencium","Rutherfordium","Dubnium","Seaborgium","Bohrium","Hassium","Meitnerium","Darmstadtium","Roentgenium","Copernicium","Nihonium","Flerovium","Moscovium","Livermorium","Tennessine","Oganesson"}
+for i, elem in ipairs(prvky) do
+minetest.register_craftitem('chemistry:'..elem..'', {
+	description = nazvy[i],
+	inventory_image = elem..'.png',
+})
+end

init.lua

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+dofile(minetest.get_modpath("chemistry").."/elements.lua")
+dofile(minetest.get_modpath("chemistry").."/core.lua")
+dofile(minetest.get_modpath("chemistry").."/recepies.lua")

mod.conf

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+name = chemistry
+depends = default, hopper
+description = Adds a way to turn one item into another.

recepies.lua

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+register_chemical_recepie("default:dirt","chemistry:Si","chemistry:Ar","chemistry:Si","chemistry:Ar","chemistry:Si","chemistry:Ar","chemistry:Si","chemistry:Ar","chemistry:Si")
+register_chemical_recepie("default:sand","chemistry:Ar","chemistry:Si","chemistry:Ar","chemistry:Si","chemistry:Ar","chemistry:Si","chemistry:Ar","chemistry:Si","chemistry:Ar")