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2 of 9 |  |
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J-2
3.
(Exp C) A certain cobalt hydrate was assayed in an analytical laboratory. After the addition of six
drops of 1.0 M AgNO3 in HNO3 to the hydrate solution, a white curdy precipitate was formed. The
mass of the anhydrous salt was 3.251g and the mass of water lost was 2.750 g. The unknown hydrate
is:
a.
CoCl2
2 H2O
b.
CaBr2
9 H2O
c.
CoSO
4
4 H2O
d.
CoCl2
6 H2O
e.
CoBr2
10 H2O
4.
(Exp D) A student recorded the following data when collecting nitrogen gas in a buret above water:
barometric pressure
720.0 mm Hg
temperature
23.3
oC
height of water column
3.30 cm
What is the pressure of nitrogen, N2, gas (in mm of Hg) under these conditions?
a.
665.5
b.
696.1
c.
698.3
d.
720.0
e.
743.9
5.
(Exp E) The following reaction was used to study chemical equilibrium:
Fe
3+
(aq)
+ NCS
-
(aq)
[Fe(NCS)]
2+
(aq)
(pale yellow) (colorless) (deep rust-red)
The color of the equilibrium solution could be lightened by adding which of the following reagents to the
equilibrium solution?
a.
NaOH
(aq)
b.
NaNO
3(aq)
c.
Fe(NO3)
3(aq)
d.
KNCS
(aq)
e.
[Fe(NCS)]
2+
(aq)
