,1 3~
Date:
Name:
Lab Partner(s):
I /'LO/'J:L.
Preparation of a Compound & Calculation of an Empirical Formula
Prelaboratory Questions
1. An unknown oxide of mercury decomposes when heated to form mercury metal
and oxygen gas. When a 1.048 g sample of this unknown is heated, 0.971 g of
mercury remains.
a. Calculate the moles of mercur:y, and moles of oxygen in the compound .
J-1\o\e.s H'}:
C) 1 q, 'S ')(. l,_Mo\
\
t.oo,Sq~
~ole.s Dz..~ 0 .011~')(
:;; O.0O'·H14i
-.i~"'~l(
.-. ~i\Wf
,;,,ot Ha.. ( 4 .Flf 'I( 10'1 fYlol
'
U'\OJ ·o - c .004~ r,io\ 0
l~l,Qt:
b. What is the empirical formula of this oxide?
Ll-l50
2..H~
-t
Ot...
2. A side reaction in today's experiment occurs between some of the magnesium
and the nitrogen gas, N2.
a. Write a balanced chemical equation for this reaction .
b. The magnesium nitride can be converted to magnesium oxide by the
addition of water. Write a balanced chemical equation for this reaction.
H3,~L t
..3 l-12,0
]
MjD +
2..NH:1
3. Suppose 1.087g of magnesium is heated in air. What is the theoretical amount of
magnesium oxide that should be produced?
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L
4. Calculate the percent by mass of molybdenum and sulfur in Mo2Ss.
Ho x 2..x. q s-.ct,
" Sx. 1'l.0 -to S
M.01.,~ 5 ::.
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