Regents Chemistry Test Preparation Practice

    Acidity Ph And Indicators

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    Base your answers to questions 7 on the information below and on your knowledge of chemistry.

    A sample of normal rainwater has a pH value of 5.6 due to dissolved carbon dioxide gas from the atmosphere. Acid rain is formed when other gases, such as sulfur dioxide, dissolve in rainwater, which can result in lake water with a pH value of 4.6. The equation below represents the reaction of water with SO2(g).

    acidity-ph-and-indicators fig: chem12020-exam_g13.png

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    Base your answers to questions 8 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.

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

    A student is to determine the concentration of an NaOH(aq) solution by performing two different titrations. In a first titration, the student titrates 25.0 mL of 0.100 M H2SO4(aq) with NaOH(aq) of unknown concentration.

    In a second titration, the student titrates 25.0 mL of 0.100 M HCl(aq) with a sample of the NaOH(aq). During this second titration, the volume of the NaOH(aq) added and the corresponding pH value of the reaction mixture is measured. The graph below represents the relationship between pH and the volume of the NaOH(aq) added for this second titration.

    arrhenius-acids-and-bases fig: chem82018-exam_g12.png

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

    Carbon dioxide is slightly soluble in seawater. As carbon dioxide levels in the atmosphere increase, more CO2 dissolves in seawater, making the seawater more acidic because carbonic acid, H2CO3(aq), is formed.

    Seawater also contains aqueous calcium carbonate, CaCO3(aq), which is used by some marine organisms to make their hard exoskeletons. As the acidity of the sea water changes, the solubility of CaCO3 also changes, as shown in the graph below.

    solutions fig: chem62018-exam_g30.png

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    Base your answers to questions 12 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.

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

    The hydrangea is a flowering plant. The color of the flowers it produces can change depending on the pH value of the soil in which the plant grows. Adding aluminum sulfate makes the soil more acidic and adding calcium hydroxide makes the soil more basic.

    A student performed an experiment by varying soil pH and recording the color of the flowers. The following table summarizes the results of the experiment.

    significent-figures-conversions fig: chem12017-exam_g18.png

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

    A company produces a colorless vinegar that is 5.0% HC2H3O2 in water. Using thymol blue as an indicator, a student titrates a 15.0-milliliter sample of the vinegar with 43.1 milliliters of a 0.30 M NaOH(aq) solution until the acid is neutralized.

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

    The incomplete data table below shows the pH value of solutions A and B and the hydrogen ion concentration of solution A.

    acidity-ph-and-indicators fig: chem62016-exam_g11.png

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