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General Chemistry Laboratory Final Exam, Lab Reports of Chemistry

Navajo Technical University (NTU)Chemistry

All combined questioned are explained in final lab exam

Typology: Lab Reports

2020/2021

Uploaded on 05/11/2021

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991E-1
General Chemistry Laboratory Final Exam 2011/01/07
Name: Department: Student ID No.:
Note:
Time: 12:20~13:10
Write down the answers on the test sheet.
There are 20 questions in the test, 4 points for each and the total score is 80.
The questions marked with * has only one answer.
Atomic mass (amu): O = 16.0, Cu = 63.6, S = 32.1, R = 0.082 L atm/mol K
Experiment 1 Molar volume of nitrogen gas
1. According to the experiment, which statement is correct?
NO2
－
(aq) + H2NSO3H (s) → HSO4
－
(aq) + H2O(l) + N2(g)
(A) Sulfamic acid (H2NSO3H) is the oxidant.
(B) Sodium nitrite (NaNO2) is a hygroscopic and white to slight yellowish crystal.
(C) Nitrogen dioxide (NO2) is the by-product of the reaction.
(D) The theoretical molar volume of nitrogen gas is 22.4 L at standard temperature and pressure.
2. Which of the following measurement has four significant figures?
(A) 298.0 K (B)760.2 mmHg (C) 314.5 mL (D) 0.022 g
Experiment 3 Determination of the chemical formula of a compound
3. According to the experiment, which statement is correct?
(A) Copper oxide shows red color.
(B) Calcium chloride is the reducing agent in the experiment.
(C) We use zinc metal react with hydrochloric acid to produce hydrogen gas.
(D) The reaction of zinc and HCl(aq) is exothermic.
Experiment 6 The enthalpies of reactions
4. According to the experiment, which enthalpy change of reaction is correct?
(A) CH3COOH(aq) + NaOH(aq) → CH3COONa(aq) + H2O(l) ∆H > 0
(B) NH4NO3(s) + H2O(l) → NH4+(aq) + NO3-(aq) ∆Hsoln > 0
(C) Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) ∆H > 0
(D) MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O(l) ∆H > 0
*5. Calculate the molar enthalpy of combustion of ethanol according to the following data:
C
2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l)
ΔHf0(H2O(g)) = -242 kJ /mol; ΔHf0(H2O(l)) = -290 kJ /mol;
ΔHf0(CO2(g)) = -390 kJ /mol; ΔHfo(C2H5OH(l)) = -280.0 kJ/mol
(A) -1226 kJ /mol (B) -400 kJ /mol (C) -352 kJ /mol (D) -1370 kJ /mol
Experiment 8 Acid-base indicators and pH determination
6. Which of the following 0.10 M solution is basic (pH > 7)?
(A) CH3COONa (B) NH4Cl (C) NaHCO3 (D) Na3PO4
*7. The Ka value of an acid-base indicator is 1 × 10-5, then the indicator changes color in the range
(A) pH 3~5 (B) pH 4~6 (C) pH 5~8 (D) pH 4~10
pf3

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General Chemistry Laboratory Final Exam 2011/01/

Name: Department: Student ID No.:

Note: — Time: 12:20~13: — Write down the answers on the test sheet. — There are 20 questions in the test, 4 points for each and the total score is 80.

— The questions marked with * has only one answer.

— Atomic mass (amu): O = 16.0, Cu = 63.6, S = 32.1, R = 0.082 L atm/mol K

Experiment 1 Molar volume of nitrogen gas

  1. According to the experiment, which statement is correct? NO 2 － (aq) + H 2 NSO 3 H (^) (s) → HSO 4 － (aq) + H 2 O( l ) + N2(g) (A) Sulfamic acid (H 2 NSO 3 H) is the oxidant. (B) Sodium nitrite (NaNO 2 ) is a hygroscopic and white to slight yellowish crystal. (C) Nitrogen dioxide (NO 2 ) is the by-product of the reaction. (D) The theoretical molar volume of nitrogen gas is 22.4 L at standard temperature and pressure.
  2. Which of the following measurement has four significant figures? (A) 298.0 K (B)760.2 mmHg (C) 314.5 mL (D) 0.022 g

Experiment 3 Determination of the chemical formula of a compound

  1. According to the experiment, which statement is correct? (A) Copper oxide shows red color. (B) Calcium chloride is the reducing agent in the experiment. (C) We use zinc metal react with hydrochloric acid to produce hydrogen gas. (D) The reaction of zinc and HCl (^) (aq) is exothermic.

Experiment 6 The enthalpies of reactions

  1. According to the experiment, which enthalpy change of reaction is correct? (A) CH 3 COOH(aq) + NaOH(aq) → CH 3 COONa (^) (aq) + H 2 O(l) ∆H > 0 (B) NH 4 NO (^) 3(s) + H 2 O(l) → NH 4 +(aq) + NO 3 - (aq) ∆Hsoln > 0 (C) Mg(s) + 2HCl (^) (aq) → MgCl2(aq) + H2(g) ∆H > 0 (D) MgO(s) + 2HCl(aq) → MgCl (^) 2(aq) + H 2 O(l) ∆H > 0

*5. Calculate the molar enthalpy of combustion of ethanol according to the following data: C 2 H 5 OH(l) + 3O2(g) → 2CO2(g) + 3H 2 O(l) ΔHf^0 (H 2 O( g )) = -242 kJ /mol; ΔHf^0 (H 2 O( l )) = -290 kJ /mol; ΔHf^0 (CO2( g )) = -390 kJ /mol; ΔHfo^ (C 2 H 5 OH(l)) = -280.0 kJ/mol (A) -1226 kJ /mol (B) -400 kJ /mol (C) -352 kJ /mol (D) -1370 kJ /mol

Experiment 8 Acid-base indicators and pH determination

  1. Which of the following 0.10 M solution is basic (pH > 7)? (A) CH 3 COONa (B) NH 4 Cl (C) NaHCO 3 (D) Na 3 PO 4

*7. The Ka value of an acid-base indicator is 1 × 10-5^ , then the indicator changes color in the range (A) pH 3~5 (B) pH 4~6 (C) pH 5~8 (D) pH 4~

Experiment 9 Solubility Rules

  1. Which of the following pair of solutions will form precipitate while mix together?

(A) 0.3 M KNO 3 and 0.3 M Na 2 CO 3 (B) 0.3 M NaCl and 0.3 M Fe(NO 3 ) (^3) (C) 0.3 M Pb(NO 3 ) 2 and 0.3 M Na 3 PO 4 (D) 0.3 M Na 2 SO 4 and 0.3 M Co(NO 3 ) (^3)

  1. Choose the reagent that can be used to separate the Hg 2 2+^ and Al 3+^ cations?

(A) NaCl (^) ( aq ) (B) Na 2 CO3( aq ) (C) Na 3 PO4( aq ) (D) NaNO3( aq )

Experiment 10 Qualitative Analysis of Cation Group 1

  1. Which of the following description of color is correct?

(A) PbCrO4(s), yellow (B) Hg 2 Cl (^) 2(s), black (C) Ag(NH 3 ) 2 +(aq), deep blue (D) PbCl (^) 2(s), white

Experiment 12 Quantitative analysis of vitamin C

*11. In the experiment, a vitamin C tablet was dissolved in water and diluted to 100.0 mL. A student took 50.0 mL of solution to titrate. The titration volume of 0.0250 M KIO3(aq) was 15.80 mL. Calculate the ascorbic acid content per tablet. (The molar mass of vitamin C is 176 g/mol) IO 3 － (aq) + 5I－ (aq) + 6H+(aq) → 3I 2 + H 2 O(l) C 6 H 8 O 6 + I 2 → C 6 H 6 O 6 + 2I - (aq) + 2H+(aq) (A) 69.5 mg (B) 209 mg (C) 834 mg (D) 417 mg

  1. According to the experiment, which of the following statement is correct? (A) Vitamin C is also called ascorbic acid. (B) Iodide ion (I - ) react with starch indicator to form blue complex. (C) Vitamin C is an ionic compound and soluble in water. (D) Vitamin C is used as a reducing agent.

Experiment 13 Determination of solubility product constant of silver acetate

  1. Which of the following would affect the Ksp value of silver acetate (CH 3 COOAg)? (A) Temperature (B) pH value of solution (C) Common ions (D) Pressure
  2. According to the experiment, which of the following description of color is correct? (A) CH 3 COOAg (^) (s), white (B) AgSCN(s), white (C) [FeSCN]2+(aq), white (D) Fe 3+(aq), red

Experiment 16 The buffer solutions

*15. According to the experiment, the plots were obtained as shown. Which of the ordering of buffer capacity is correct? (A) A>B>C>D (B) A>C>D>B (C) A>B>D>C (D) B>D>C>A

Experiment 17 Quantitative analysis of cobalt(II) ions

  1. According to the experiment, which of the following statement is true? (A) The color of Co2+(aq) ion is pink. (B) Acetone is an organic solvent with low dielectric constant. (C) We use 10-mL graduated cylinder to prepare [Co(SCN) 4 ]2-^ sample solution. (D) The complex ion, [Co(SCN) 4 ]2-^ , absorbs blue color of light and appears blue.