4: Zinc and Iodine Lab

Physical Description

Before	After
clear liquid	clear liquid
small, silver flakes of zinc a bit larger than sand	dull, gray flakes of zinc, the same size
small, blue-silver sparkly iodine, like graphite chunks

Quantitative Measurements

Before	After
mass of zinc used - 1.95g	mass of zinc left over - 1.42g
mass of iodine used - 1.96g	mass of off-white solid - 2.95g
10 mL of vinegar

Particle Diagram

During the reaction, the beaker became hot, and the liquid started changing from clear to yellow, 
to reddish-brown, to green, and back to clear. 

Chemical Symbols/Equation

Explanation of the Reaction

When zinc and iodine are mixed together in vinegar, the chemical equation is Zn + I₂ → ZnI₂. The end of this lab resulted in 2 products: one was the supposed zinc iodide, and the other was the leftover zinc. We knew that the vinegar was only there to facilitate this chemical reaction, and was not a part of the reaction itself, so we were only left with the zinc and iodine. Originally, there was an equal amount of both zinc and iodine, but in the end, there was leftover zinc, thus meaning that not all of the zinc reacted with the iodine. We then found the ratio of the iodine to the zinc that partook in the reaction, which was ≈ 2. This suggested that There were twice as many iodine atoms than zinc atoms, meaning Zn + I₂ → ZnI₂.