Regents Chemistry Test Preparation Practice

    Electron Dot Diagrams (Lewis Structures)

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    Base your answers to questions 4 on the information below and on your knowledge of chemistry.

    Solid sodium chloride, also known as table salt, can be obtained by the solar evaporation of seawater and from underground mining. Liquid sodium chloride can be decomposed by electrolysis to produce liquid sodium and chlorine gas, as represented by the equation below.

    2NaCl(ℓ) → 2Na(ℓ) + Cl2(g)

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    Base your answers to questions 5 on the information below and on your knowledge of chemistry.

    The formulas and names of four chloride compounds are shown in the table below.

    octet-rule fig: chem12019-exam_g11.png

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

    The equation below represents a chemical reaction at 1 atm and 298 K.

    2H2(g) + O2(g) → 2H2O(g)

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

    The radius of a lithium atom is 130. picometers, and the radius of a fluorine atom is 60. picometers. The radius of a lithium ion, Li+, is 59 picometers, and the radius of a fluoride ion, F, is 133 picometers.

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

    The Lewis electron-dot diagrams for three substances are shown below.

    electron-dot-diagrams-(lewis-structures) fig: chem12016-exam_g7.png

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

    The diagrams below represent ball-and-stick models of two molecules. In a ball-and-stick model, each ball represents an atom, and the sticks between balls represent chemical bonds.

    electron-dot-diagrams-(lewis-structures) fig: chem12015-exam_g17.png

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

    Silver-plated utensils were popular before stainless steel became widely used to make eating utensils. Silver tarnishes when it comes in contact with hydrogen sulfide, H2S, which is found in the air and in some foods. However, stainless steel does not tarnish when it comes in contact with hydrogen sulfide.

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