Short Form Memo-Style Lab Reports
TO: Joan Richmond, Professor
FROM: Melissa Wood, Student
LAB PARTNER: Megan Miller, Lindsy Danforth
DATE: April 14, 2009
SUBJECT: Formation of Ionic Compound
Purpose: The purpose of this lab was to see the formation of ionic compounds and
understand the reaction that takes place.
Summary: I discovered that a each reaction required a different amount of HCl even
though we all roughly had the same amount of metal.
Procedures: The first thing we did was each set up our ring stand, crucible, and
Bunsen burner. Next we lit the burner and heated the crucible for about ten minutes to
dry out any moisture. We then weighed out our dried crucible, after it had cooled. We
then had to weigh out 1.0 g of zinc powder and recorded its mass, and then weighed
the zinc in the cooled crucible. We then added fifteen milliliters of 6 M HCl to the
crucible and zinc and watched it fizz and bubble, swirling the mixture until it stopped
fizzing. The fifteen mL of HCl wasn’t enough for my zinc to totally react so I added
another 5-mL of acid until all the metal was dissolved. After all the zinc was gone we
each set up a steam bath, setting a half-full beaker of water over a flame and heated it
to a low boil. Then we has to place the crucible on the steam bath and heat gently until
most of the liquid had evaporated, making sure that we didn’t melt the salt produced
by the reaction. We were then supposed to weigh the crucible with the dried salt but
we had run out of time.
Drying out the crucible was one of the more important things, if the crucible wasn’t
completely dry when we added the zinc it would’ve absorbed the moisture and our
weight reading would’ve been off. Also being pretty cautious with our HCl making sure
we didn’t get any on our skin or clothes. Also the hydrogen gas that was released by
adding the acid in with the metal was flammable.
Results:
Calculations:
Mass of Salt produced
(g)
Mass of Chloride (g)
Moles of Metal
Moles of Chloride
Molar Ratios
Percent composition
Mine
2.35
Megan
2.53
Lindsy
2.31
1.34
.015
.038
.038/.015
Zn = 26.95% Cl =
73.05%
1.50
.015
.042
.042/.015
1.31
.015
.037
.037/.015
Zn = 26.95% Cl =
73.05%
My calculations show that Lindsy and I have the same molar ratio (.038 Cl over .015
Zn) where as Megan’s Chloride is slightly higher yet her Zinc is the same. This could be
attributed to human error or my not doing the calculation right but Lindsy and I both
had the same ratios so I’m unsure of that. Also Megan’s amount of salt produced was
nearly .2 grams higher than both Lindsy and mine; also Megan’s mass of Chloride is
also about .2grams higher so maybe that could be why our final numbers are different.
From this I’d conclude that with more salt produced by the reaction the higher the
mass of Chloride is which then gives you a different molar ratio and percent
composition.
Mine
Dried Crucible mass (g)
Zn Mass (g)
Volume of HCl (mL)
Mass crucible + salt (g)
131.02
1.01
19.9
133.37
Megan
132.98
1.03
14.6
135.51
Lindsy
133.32
1.00
14.8
135.63