Illustrated Guide to Home Chemistry Experiments

Chapter 9 Laboratory: Introduction to Chemical Reactions and Stoichiometry 165

dAL: The waste material from this lab can be ISpoS

ground to powder and flushed down the drain with

plenty of water.

FIGURE 9-1: Iron and sulfur reacting to form iron sulfide

TABLE 9-1:

Observe a composition reaction—observed and calculated data.

CUTIOA nS

Iron(II) sulfide powder is pyrophoric, which means that it

can catch fire spontaneously. Crush it gently, and don’t

attempt to powder it too finely. If it does catch fire, dump

the whole mass into the pail of water.

z

CUTIOA nS

In addition to smelling awful, hydrogen sulfide gas

is extremely toxic—more so than hydrogen cyanide.

Hydrogen sulfide is particularly pernicious, because

the human nose rapidly becomes desensitized to its

odor. That means it’s possible to be exposed to a lethal

concentration of hydrogen sulfide without noticing a

particularly strong odor. Use only a few tiny grains of

iron(II) sulfide, and limit your exposure to hydrogen

sulfide to a short, wafted sniff. Never put the test tube

under your nose.

z

has proceeded to completion and there is not an excess

of elemental iron present, the product should not be

attracted to the magnet.

Sulfur does not react with hydrochloric acid under normal

conditions. Iron reacts with hydrochloric acid to form

hydrogen gas. Iron(II) sulfide reacts with hydrochloric

acid to form hydrogen sulfide, which has an intense odor

of rotten eggs. Test for the presence of iron(II) sulfide

by adding a few sand-size grains of your product to

a test tube that contains about 1 mL of concentrated

hydrochloric acid and checking for the odor of hydrogen

sulfide. (Note that concentrated hydrochloric acid itself

has a strong, distinctive odor, but the odor of hydrogen

sulfide is quite different.) Don’t put the test tube under

your nose to check for hydrogen sulfide. Instead, hold the

test tube well away from your face and use your hand to

waft the odor from the test tube toward your nose.

Item Data

A. Mass of tin can lid ______.______ g

B. Mass of iron filings ______.______ g

C. Mass of sulfur ______.______ g

D. Moles of iron filings ____.________ moles

E. Moles of sulfur ____.________ moles

F. Expected mass of FeS ______.______ g

G. Mass of tin can lid + product ______.______ g

H. Actual mass of product (G – A) ______.______ g

I. Percent yield (100 · H/F) ______.______ %

17.