How to make a spooky Halloween keychain

DIY Adorable and spooky keychain

Safe­ty pre­cau­tions

Only un­der adult su­per­vi­sion.

Equip­ment and reagents

  • cop­per­ized plate;
  • sand­pa­per;
  • sten­cil;
  • 16g ta­ble salt;
  • 6g cop­per(II) sul­fate;
  • 40mL hot wa­ter;
  • cup.

Step-by-step in­struc­tions

Pol­ish a cop­per­ized plate with sand­pa­per. Ap­ply a sten­cil to the plate and place it in a cup. Add 6g cop­per(II) sul­fate and 16g sodi­um chlo­ride. Add 40mL hot wa­ter and stir the re­sult­ing mix­ture. 10 min­utes lat­er, re­trieve the plate. The cop­per on the plate dis­solved! Rinse with wa­ter and re­move the stick­er – the im­age stays put!

Pro­cess­ de­scrip­tion

The sur­face of the plate is cov­ered with oils, dust, and dirt par­ti­cles. We use sand­pa­per to re­move them, ex­pos­ing the metal­lic cop­per and mak­ing it more re­ac­tive. The cop­per sul­fate dis­solves in wa­ter to yield cop­per(II) Cu²⁺ and sul­fate ions. Cu²⁺ has two few­er elec­trons than the neu­tral cop­per Cu⁰ on the cop­per plate. When these two ver­sions of cop­per meet each oth­er, elec­trons from the metal­lic cop­per Cu⁰ trans­fer to the cop­per(II) ions Cu²⁺, and they both turn into cop­per(I) Cu¹⁺ ions. As a re­sult, the met­al dis­solves off the poly­mer plate ev­ery­where ex­cept the area pro­tect­ed with the sten­cil. Looks cool, right?

And did you know? A sim­i­lar ex­per­i­ment is in­clud­ed in the “Etch­ing and Plat­ing” set from the MEL Chem­istry sub­scrip­tion!