Regents Chemistry Test Preparation Practice

    Octet Rule

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

    Sir William Ramsey is one scientist credited with identifying the noble gas argon. Sir Ramsey separated nitrogen gas from the air and reacted it with an excess of magnesium, producing solid magnesium nitride. However, a small sample of an unreactive gas remained with a density different from the density of the nitrogen gas. Sir Ramsey identifi ed the unreactive gas as argon and later went on to discover neon, krypton, and xenon.

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    Base your answers to questions 9 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 10 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 12 on the information below and on your knowledge of chemistry.

    Potassium phosphate, K3PO4, is a source of dietary potassium found in a popular cereal. According to the Nutrition-Facts label shown on the boxes of this brand of cereal, the accepted value for a one-cup serving of this cereal is 170. milligrams of potassium. The minimum daily requirement of potassium is 3500 milligrams for an adult human.

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    Base your answers to questions 13 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 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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