Regents Chemistry Test Preparation Practice

    Concentration Of A Solution

    1
    2
    3
    4
    5

    Base your answers to questions 6 on the information below.

    In a titration, a few drops of an indicator are added to a flask containing 35.0 milliliters of HNO3(aq) of unknown concentration. After 30.0 milliliters of 0.15 M NaOH(aq) solution is slowly added to the flask, the indicator changes color, showing the acid is neutralized.

    6

    Base your answers to questions 7 on the information below.

    Ammonium chloride is dissolved in water to form a 0.10 M NH4Cl(aq) solution. This dissolving process is represented by the equation below.

    physical-behavior-of-matter, concentration-of-a-solution fig: chem12013-exam_g18.png

    7

    Base your answers to questions 8 on the information below.

    Nitrogen gas and oxygen gas make up about 99% of Earth’s atmosphere. Other atmospheric gases include argon, carbon dioxide, methane, ozone, hydrogen, etc.

    The amount of carbon dioxide in the atmosphere can vary. Data for the concentration of CO2(g) from 1960 to 2000 are shown in the table below.

    periodic-table, identification-of-element fig: chem12013-exam_g19.png

    8

    Base your answers to questions 9 on the information below and on your knowledge of chemistry.

    In a titration, 50.0 milliliters of 0.026 M HCl(aq) is neutralized by 38.5 milliliters of KOH(aq).

    9

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

    Seawater contains dissolved salts in the form of ions. Some of the ions found in seawater are Ca2+, Mg2+, K+, Na+, Cl, HCO3, and SO42−. An investigation was conducted to determine the concentration of dissolved salts in seawater at one location. A 300.-gram sample of the seawater was placed in an open container. After a week, all the water had evaporated and 10. grams of solid salts remained in the container.

    10

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

    Copper can be used for water pipes in homes. When the pipes corrode, copper atoms oxidize to form Cu2+ ions in the water.

    A homeowner has a water quality report prepared for a sample of water taken from pipes in the home. According to the report, the 550.-gram sample contains 6.75 × 10−4 gram of dissolved Cu2+ ions.

    11

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

    A NaOH(aq) solution and an acid-base indicator are used to determine the molarity of an HCl(aq) solution. A 25.0-milliliter sample of the HCl(aq) is exactly neutralized by 15.0 milliliters of 0.20 M NaOH(aq).

    12

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

    During a titration, 10.00 mL of acetic acid, HC2H3O2(aq), is completely neutralized by adding 12.50 mL of 0.64 M sodium hydroxide, NaOH(aq).

    13

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

    A solution of ethylene glycol and water can be used as the coolant in an engine-cooling system. The ethylene glycol concentration in a coolant solution is often given as percent by volume. For example, 100. mL of a coolant solution that is 40.% ethylene glycol by volume contains 40. mL of ethylene glycol diluted with enough water to produce a total volume of 100. mL. The graph below shows the freezing point of coolants that have different ethylene glycol concentrations.

    physical-behavior-of-matter, classification-of-matter fig: chem12017-exam_g17.png

    14

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

    A student constructs an electrochemical cell. A diagram of the operating cell and the unbalanced ionic equation representing the reaction occurring in the cell are shown below.

    The blue color of the solution in the copper half-cell indicates the presence of Cu2+ ions. The student observes that the blue color becomes less intense as the cell operates.

    oxidation-reduction, electrochemical-cell, voltaic-cell, oxidation-reduction, electrochemical-cell, voltaic-cell fig: chem12019-exam_g14.png

    15