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mpound: Chemical Properties
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Experiment 2 Prelaboratory Assignment
Identification of a Compound:
Chemical Properties
Date
Lab Sec.
Name
Desk No.
1. Experimental Procedure, Part A.
a. What is the criterion for clean glassware?
b. What is the size and volume of a "small, clean test tube"?
7a
2. Experimental Procedure, Part A.2. Describe the technique for testing the odor of a chemical.
17a
3. Identify at least five observations that are indicative of a chemical reaction.
4. Depending upon the tip of a dropper pipet, there are approximately 20 drops per milliliter of water. The Experimental
Procedure, Parts A and B, indicates the addition of 5–10 drops of each solution (Figure 2.2a) to the test tubes. Calcu-
late the volume range in milliliters for the solution.
Experiment 2
63
5. Experimental Procedure, Part A. The substances NaCl, Na2CO3, MgSO4, and NH CI, which are used for test solutions,
are all soluble ionic compounds. For each substance, indicate the ions present in its respective test solution.
NaCl:
Na Coz:
MgSO4
NHẠCl:
No SIM
3:54 AM
T @ 1 © 28%
'he tip of a dropper pipet, there are approximately 20 drops per milliliter of water. The Experimental
and B, indicates the addition of 5-10 drops of each solution (Figure 2.2a) to the test tubes. Calcu-
Tlution
74 of AGO
х 208043047-Laborator...
Experiment 2
63
5. Experimental Procedure, Part A. The substances NaCl, Na,C03, MgSO4, and NH_CI, which are used for test solutions,
are all soluble ionic compounds. For each substance, indicate the ions present in its respective test solution.
NaCl:
Na C03:
MgSO4:
NHẠCl:
6. Three colorless solutions in test tubes, with no labels, are in a test tube rack on the laboratory bench. Lying beside the
test tubes are three labels: potassium iodide, KI; silver nitrate, AgNO3; and sodium sulfide, Na S. You are to place the
labels on the test tubes using only the three solutions present. Here are your tests:
A portion of test tube 1 added to a portion of test tube 3 produces a yellow silver iodide precipitate.
A portion of test tube 1 added to a portion of test tube 2 produces a black silver sulfide precipitate.
a. Your conclusions are:
Test tube 1
.
.
Test tube 2
Test tube 3
b. Write the balanced equation for the formation of silver iodide, Agl, from a mix of two selected solutions provided
above.
c. Write the balanced equation for the formation of silver sulfide, Ag2S, from a mix of two selected solutions provided
above.
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Identification of a Compound: Chemical Properties
Solution No.
1
2
3
5
Unknown
Reagent A
Reagent B
Reagent C
Compound of unknown is the same as Solution No.
Experiment 2
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Laboratory Questions
Circle the questions that have been assigned.
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?
2. What test reagent used in this experiment will distinguish a soluble Cl salt from a soluble SO2 salt? What is the
distinguishing observation?
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
b. zinc chloride and silver nitrate
c. magnesium chloride and sodium hydroxide
d. ammonium nitrate and sodium hydroxide
4. Three colorless solutions in test tubes, with no labels, are in a test tube rack on the laboratory bench. Lying beside the
tests tubes are three labels: 0.10 M Na2CO3, 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 test tube 1 added to a similar volume of the solution in test tube 2 produces no vis-
ible reaction but the solution becomes warm.
• A few drops of the solution from 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.
5. Three colorless solutions in test tubes, with no labels, are in a test tube rack on the laboratory 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 procedure:
• A portion of test tube 1 added to a portion of test tube 2 produces carbon dioxide gas, 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?
b. What would you expect to happen if a portion of test tube 1 is added to a portion of test tube 3?
6. For individual solutions of the cations Agt, Ba²+, Mg2+, and Cu2+, the following experimental observations were
collected:
NH3(aq)
HCl(aq) H SO_(aq)
No change
White ppt
No change
No change
No change
White ppt
No change No change
Blue ppt/deep blue soln with excess No change No change
*Example: When an aqueous solution of hydrochloric acid is added to a solution containing Agt, a white precipitate (ppt) forms.
From these experimental observations,
a. identify a reagent that distinguishes the chemical properties of Ag+ and Mg2+. What is the distinguishing
observation?
b. identify a reagent that distinguishes the chemical properties of HCl and H2SO4. What is the distinguishing
observation?
c. identify a reagent that distinguishes the chemical properties of Ba²+ and Cu²+. What is the distinguishing observa-
tion?
*d. identify a reagent that distinguishes the chemical properties of Cu2+ and Mg2+. What is the distinguishing obser-
vation?
White ppt
Ag+
Ba2+
Mg2+
Cu2+
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Identification of a Compound: Chemical Properties
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