Regents Chemistry Test Preparation Practice

    Table E Selected Polyatomic Ions

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    Base your answers to questions 7 on the information below.

    A total of 1.4 moles of sodium nitrate is dissolved in enough water to make 2.0 liters of an aqueous solution. The gram-formula mass of sodium nitrate is 85 grams per mole.

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    Base your answers to questions 8 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 9 on the information below and on your knowledge of chemistry.

    In a titration using a pH meter, 16.0 milliliters of 0.18 M NaOH(aq) exactly neutralizes a 24.0-milliliter sample of HCl(aq) in a flask. During this laboratory activity, appropriate safety equipment was used and safety procedures were followed.

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

    Four different samples of NaNO3(aq) are each evaporated to dryness. The solution volume and mass of the dry NaNO3(s) of each sample are recorded in the table below.

    moles-and-stoichiometry, formula-mass-and-gram-formula-mass, moles-and-stoichiometry, compounds fig: chem82023-exam_g21.png

    The number of moles of NaNO3(s) of each sample was then calculated and used to produce the graph below.

    moles-and-stoichiometry, formula-mass-and-gram-formula-mass, moles-and-stoichiometry, compounds fig: chem82023-exam_g20.png

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