Chemistry worksheet
    Topic: Electrolyte
    Electrolyte
    1

    A 0.050 M aqueous solution of which compound is the best conductor of electric current?

    (1) C3H7OH

    (2) C6H12O6

    (3) MgSO4

    (4) K2SO4

    2

    Which statement describes an electrolyte?

    (1) An electrolyte conducts an electric current as a solid and dissolves in water.

    (2) An electrolyte conducts an electric current as a solid and does not dissolve in water.

    (3) When an electrolyte dissolves in water, the resulting solution conducts an electric current.

    (4) When an electrolyte dissolves in water, the resulting solution does not conduct an electric current.

    3

    Which solution is the best conductor of an electric current?

    (1) 0.001 mole of NaCl dissolved in 1000. mL of water

    (2) 0.005 mole of NaCl dissolved in 1000. mL of water

    (3) 0.1 mole of NaCl dissolved in 1000. mL of water

    (4) 0.05 mole of NaCl dissolved in 1000. mL of water

    4

    Why is potassium nitrate classified as an electrolyte?

    (1) It is a molecular compound.

    (2) It contains a metal.

    (3) It can conduct electricity as a solid.

    (4) It releases ions in an aqueous solution.

    5

    Which substance is an electrolyte?

    (1) CCl4

    (2) C6H12O6

    (3) SiO2

    (4) H2SO4

    6

    The electrical conductivity of an aqueous solution depends on the concentration of which particles in the solution?

    (1) molecules

    (2) electrons

    (3) atoms

    (4) ions

    7

    Which compound is an electrolyte?

    (1) H2O

    (2) C2H6

    (3) H3PO4

    (4) CH3OH

    8

    Which substance is an electrolyte?

    (1) O2

    (2) Xe

    (3) C3H8

    (4) KNO3

    9

    Which compounds are classified as electrolytes?

    (1) KNO3 and H2SO4

    (2) KNO3 and CH3OH

    (3) CH3OCH3 and H2SO4

    (4) CH3OCH3 and CH3OH

    Base your answers to questions 10 on the information below and on your knowledge of chemistry.

    The electrical conductivity of three aqueous solutions was tested at room temperature. A 0.1 M HCl(aq) solution conducted, but a 6.0 M HCl(aq) solution was a better conductor. A 0.1 M C6H12O6(aq) solution was also tested. During this laboratory activity, appropriate safety equipment was used and safety procedures were followed.

    10

    State, in terms of the concentration of ions, why the 6.0 M HCl(aq) is a better conductor of electricity than the 0.1 M HCl(aq).

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • There is a greater concentration of ions present in the 6.0 M HCl(aq) than in the 0.1 M HCl(aq).

    • The 6.0 M HCl(aq) has a higher concentration of ions.

    • Note: Do not allow credit for “more ions” because it is not in terms of concentrations of ions.

    Base your answers to questions 11 on the information below and on your knowledge of chemistry.

    In a laboratory investigation, an HCl(aq) solution with a pH value of 2 is used to determine the molarity of a KOH(aq) solution. A 7.5-milliliter sample of the KOH(aq) is exactly neutralized by 15.0 milliliters of the 0.010 M HCl(aq). During this laboratory activity, appropriate safety equipment is used and safety procedures are followed.

    11

    Explain, in terms of aqueous ions, why 15.0 mL of a 1.0 M HCl(aq) solution is a better conductor of electricity than 15.0 mL of a 0.010 M HCl(aq) solution.

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • The 1.0 M solution has a greater concentration of mobile ions than the 0.010 M solution.

    • The 0.010 M solution has fewer mobile ions.

    • The 1.0 M solution has more aqueous ions.

    Base your answers to questions 12 on the information below and on your knowledge of chemistry.

    The electrolysis of brine, a concentrated aqueous sodium chloride solution, produces three important industrial chemicals: chlorine gas, hydrogen gas, and sodium hydroxide. The diagram and equation below represent a brine electrolysis cell. Before the battery is connected, the pH value of the brine solution is 7.0.

    electrolytic-cell fig: chem82017-exam_g22.png

    12

    Explain, in terms of ions, why the aqueous solution in the cell conducts an electric current.

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • The solution contains mobile ions.

    • The solution has ions that can move.

    • The Na+(aq) and Cl(aq) move freely.

    Base your answers to questions 13 on the information below and on your knowledge of chemistry.

    Vinegar is a commercial form of acetic acid, HC2H3O2(aq). One sample of vinegar has a pH value of 2.4.

    13

    Explain, in terms of particles, why HC2H3O2(aq) can conduct an electric current.

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • The HC2H3O2(aq) has ions in water, which are mobile.

    • The charged particles move freely.

    • Acetic acid forms moveable ions in aqueous solution.

    Base your answers to questions 14 on the information below and on your knowledge of chemistry.

    In an investigation, aqueous solutions are prepared by completely dissolving a different amount of NaCl(s) in each of four beakers containing 100.00 grams of H2O(ℓ) at room temperature. Each solution is heated and the temperature at which boiling occurred is measured. The data are recorded in the table below.

    solutions fig: chem82016-exam_g16.png

    14

    Explain, in terms of ions, why the ability to conduct an electric current is greater for the solution in beaker 4 than for the solution in beaker 1.

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • The solution in beaker 4 has a greater ability to conduct an electric current because it has a greater concentration of aqueous ions than the solution in beaker 1.

    • There are fewer charged particles free to move in beaker 1.

    • There are more ions in beaker 4.

    Base your answers to questions 15 on the information below and on your knowledge of chemistry.

    A laboratory technician is given the table below and a sample of one of the three substances listed in the table. The technician makes an aqueous solution with a portion of the sample. When a conductivity tester is lowered into the solution, the lightbulb on the tester glows brightly. Another portion of the sample is placed in a heat-resistant container that is placed in an oven at 450.°C. The sample melts.

    differentiation-of-types-of-substances fig: chem12016-exam_g9.png

    15

    Explain, in terms of ions, why an aqueous solution of potassium chromate conducts an electric current.

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • An aqueous solution of potassium chromate has mobile ions that conduct electricity.

    • The K2CrO4 dissociated into mobile ions.

    • Aqueous potassium chromate has charged particles that can move.

    • The K+(aq) and CrO42−(aq) move freely.