“Exothermic,” Maya whispered, recording the temperature rise. The magnesium was even more reactive than zinc. It had ripped the copper from the solution with such force that it generated heat.
“No reaction,” Maya noted, scribbling in her book. “Copper + copper sulphate → no change. That means copper is low in the reactivity series. It can’t kick itself out of its own salt.”
Ravi, whose fingers were always a little too eager, held a small coil of magnesium ribbon. It looked like a piece of dull, grey tinsel. “This looks harmless,” he smirked. chemistry form 4 experiment 5.1
Lin dropped a small piece of copper wire into the blue liquid. They waited. One minute. Two. The copper sat at the bottom like a sleeping snake. The blue remained blue.
Maya, the cautious one, read the steps aloud. “First, we label four test tubes. One is the control.” “No reaction,” Maya noted, scribbling in her book
The solution turned from vibrant blue to a pale, cloudy colourless. The reddish-brown solid was pure, elemental copper. Zinc was the hero.
In their lab books, under , Maya wrote the final line of the story: It can’t kick itself out of its own salt
“Today,” she had announced, her voice crackling through the lab’s humid air, “you are all forensic chemists. A factory has spilled three different metals—magnesium, zinc, and copper—into a vat of copper(II) sulphate solution. Your job is to determine which metal is the ‘hero’ that reacts, and which are the ‘villains’ that remain inert.”
Maya stood up, her voice steady. “Magnesium is the most reactive, then zinc, then copper. Because a more reactive metal will displace a less reactive metal from its salt solution.”