Báo cáo hóa (1)

Experiment 2 Prelaboratory Assessment
Identification of a compond: chemical properties
1
a)
when we say clean glassware its criterion is that it obtained no any lingering
chemical that would be developed in the outcomes of a certain experiment
b)
In regards with the figure show we could see that the size of a small clean test
tube will be “ 75mm for the smallest 150mm for the smallest and also 200mm for
the the bigger one . When it come to the measure of each volume we have the
volume at 3ml the smallest 55ml for the smaller one and also we have 70ml for
the bigger one.
2
To smell the odor you place your hand above the test tube and wave in a circular
motion so the air goes towards your face
3
Five observations that indicate that a reaction occurred are change in odor,
change in color, appearing or disappearing precipitate, heat evolving or being
absorbed, and gas evolving
4. experimental procedure part A.1 referring to appendix G for the substances
listed here underline those that are soluble and circle those that are insoluble
AgNO3

NaCl

AgCl

Na2CO3 Ag2vCO3 MgSO4 Ag2SO4

5
Ionic compound

NaCl
Na2CO3
MgSO4
NH4Cl
6 a)

element
Na+
Na+
Mg2+
NH4+

element
ClCO32SO42Cl-

NH4Cl


- Test 1 tube 1 : AgNO3
- Test 2 tube 2: Na2S
- Test 3 tube 3: KI
b)
AgNO3 +KI

AgI + KNO3

c)
Na2S + 2AgNO3

Ag2S + 2NaNO3

 REPORT
A Chemical properties of know compounds
Test

NaCl

Na2CO3

MgSO4

NH4Cl

AgNO3

Light
yellow
precipit
ate
Clear

Faint
cloudy

NaOH

Cloudy
at
bottom
white

Clear

HCL

Clear

Clear,
bubbles
CO2

White
Clear
cloudy
precipit
ate
Ammoni Clear
a
gas(NH3
)
Clear
Clear

White
cloudy
on
bottom
Clear

H2O

Write formulas
Part a.1: AgCl
Ag2CO3
Ag2SO4
AgCl
no reaction
Part a.2 : no reaction
no reaction
Mg(OH)2
NH3
no reaction
Part a.3 : no reaction
CO2
no reaction
no
reaction no reaction
-Sample no of unknown solution part 4 : Y is AgNO 3
-Compound in unknown solution: silver nitrate
-Results and discussion:
In this experiment we were testing to see compounds react
with other compounds. We tested 8 different compounds


with each other to record a visual reaction. As you can tell
through our datasome of the experiments did not have a
reaction. This is normal because some compounds do not
react with each other. For each reaction we created a
chemical equation to visualize what actually happened.
When we tested AgNO3 with NaCl we saw precipitate form in
a cloudy white substance. When AgNO3 reacted with Na2CO3

the results were that a pale brownish yellow substance
appeared. This reaction produced 2 NaNO3 + Ag2CO3. When
AgNO3 reacted with MgSO4 it formed a faint cloudy
precipitate
-

In this experiment we were
testing to see compounds
react with other
compounds. We tested 8
different compounds with
each other to record a
visual reaction. As you can
tell through our data
some of the experiments
did not have a reaction.


This is normal because
some compounds do
not react with each other.
For each reaction we
created a chemical
equation to visualize what
actually happened. When
we tested AgNO3 with NaCl
we saw precipitate form in
a cloudy white
substance. When AgNO3
reacted with Na2CO3 the

results were that a pale
brownish yellow
substance appeared. This
reaction produced 2 NaNO3


+ Ag2CO3. When AgNO3
reacted with
MgSO4 it formed a faint
clou
B . chemical properties of unknown compound
Soluti
on no

Na2CO3
(1)

NaCl
(2)

NH4Cl
(3)

MgSO4
(4)

H2O
(5)

Reage No

No
Ammoni Cloudy
No
nt
reaction reaction a gas
reacti
A( Na
(NH3)
on
OH )
Reage Light
White
White
White
No
nt B
yellow
precipit precipit precipit reacti
(AgNO precipit ate
ate
ate
on
ate
3)
Reage Bubbly
No
No
No
No
nt C

reaction reaction reaction reacti
( HCl)
on
LABORATORY QUESTIONS
1. Identify a chemical reagent used in this experiment that
can be used to distinguish solid CaCl2 (soluble) from solid
CaCO3 (insoluble). What is the distinguishing observation?
-The chemical reagent used in this experiment that would
distinguish CaCl2 from CaCO3 would be HCl. If HCl is added to
CaCO3 it will fit and if added to CaCl2 it would not. The
distinguishing observation would be whether the substance
fizzed which indicated the creation of gas.
2. What test reagent used in this experiment will distinguish
a soluble Cl– salt from a soluble SO42– salt? What is the
distinguishing observation?


-Silver nitrate can be used to distinguish between a soluble
Cl- salt from a soluble SO42– salt. Cl- will form a white
precipitate and SO42– will form clear crystals.
3. Predict what would be observed (and why) from an
aqueous mixture for each of the following (all substances are
water soluble).
a. Potassium carbonate and hydrochloric acid
-By mixing the two we get potassium chloride. CO 2 and water
will also be present but no precipitate will form.
b. Zinc chloride and silver nitrate
- By mixing zinc chloride and silver nitrate we will get zinc
nitrate and silver chloride. The silver chloride will form a
precipitate because it is not soluble in water.

c. Magnesium chloride and sodium hydroxide
- By mixing magnesium chloride and sodium hydroxide, we
would get magnesium hydroxide and sodium chloride. Since
magnesium hydroxide is insoluble it will produce a
precipitate.
d. Ammonium nitrate and sodium hydroxide
-By mixing ammonium nitrate and sodium hydroxide we get
sodium nitrate, ammonia, and water. No precipitate would
form in this situation because they are all soluble.
4. Three colorless solutions in test tubes, with no labels, are
in the test tube rack on the lab bench. Lying beside the test
tubes are three labels: silver nitrate, AgNO3; hydrochloric
acid, HCl; and sodium carbonate, Na2CO3. You are to place
the labels on the test tubes using only the three solutions
present. Here is your analysis prodedure:
• A portion of test tube 1 added to a portion of test tube 2
produces CO2.
• A portion of test tube 2 added to a portion of test tube 3
produces a white silver carbonate precipitate.
a. On the basis of your observations, how would you label
the three test tubes?
Test tube 1: HCl
Test tube 2: Na2CO3


Test tube 3: AgNO3
b. What would you expect to happen if a portion of test tube
1 is added to a portion of test tube 3?
- If we mixed a portion of test tube 1 and test tube 3 then
we would get AgCl, this will form a precipitate because it

is insoluble.
5. For individual solutions of the cations Ag + , Ba2+ , Mg2+,
and Cu2+ the following experimental observations were
collected
NH3
HCl
H2SO4
a
Ag
No change
White ppt
No change
2+
Ba
No change
No change
White ppt
2+
Mg
White ppt
No change
No change
2+
Cu
Blue
No change
No change
ppt/deep
blue soln
with excess

From these experimental observations,
a. Identify a reagent that distinguishes the chemical
properties of Ag+ and Mg2+. What is the distinguishing
observation?
-The reagent that distinguishes the chemical properties
would be HCl because this forms a precipitate with Ag +
forming AgCl. If we mix it with Mg+ then we get MgCl2.
b. Identify a reagent that distinguish the chemical
properties of the HCl and the H2SO4. What is the
distinguishing observation?
-The reagent that distinguishes the chemical properties
would be Ag+, when it reacts with HCl we get AgCl which
forms a precipitate. If mixed with H2SO4 no precipitate
forms because it is soluble.
c. Identify a reagent that distinguishes the chemical
properties of Ba2+ and Cu2+. What is the distinguishing
observation?
-The reagent that distinguishes the chemical properties
would be NH3, when it reacts with Cu2+ we see a blue
+


solution form due to its reaction with ammonia. When Ba +
is mixed with NH3 a reaction will not occur because it is
soluble.
d. Identify a reagent that distinguishes the chemical
properties of Cu2+ and Mg2+. What is the distinguishing
observation?
-The reagent that distinguishes the chemical properties
would be NH3, when we react it with Cu2+ we get a blue

colored solution indicating there was a reaction. If we mix
it with Mg2+ no reaction would form
6. Three colorless solutions in the test tubes, with no
labels, are in a test tube rack on the lab bench. Lying
beside the test tubes are three labels: 0.10 M Na 2CO3,
0.10 M HCl, and 0.10 M KOH. You are to place the labels
on the test tubes using only the three solutions present.
Here are your tests:
• A few drops of the solution from the test tube 1 added
to a similar volume of the solution in the test tube 2
produces no visible reaction but the solution becomes
warm.
• A few drops of the solution from the test tube 1 added
to a similar volume of the solution in test tube 3 produces
carbon dioxide gas.
• Identify the labels for test tubes 1,2, and 3.
Test tube 1: 0.10 M HCl
Test tube 2: 0.10 M KOH
Test tube 3: 0.10 M Na2CO3

++++observation? "
The chemical reagent
used in this experiment


that would distinguish
CaCl2 from CaCO3
would be HCl. If HCl is
added to CaCO3 it will fit
and if added to CaCl2 it

would not.
The distinguishing
observation would be
whether the substance
fizzed which indicated
the
creation of ga