Regents Chemistry Exam Explanations June 2007

June 2007 Chemistry Regents #21-30

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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

Questions
Answer Explanations
21 A double carbon-carbon bond is found in a molecule of
(1) pentane       (3) pentyne
(2) pentene       (4) pentanol 2 double bond-Alkenes
-ene
22 Which changes occur when Pt²⁺ is reduced?
(1) The Pt²⁺ gains electrons and its oxidation number increases.
(2) The Pt²⁺ gains electrons and its oxidation number decreases.
(3) The Pt²⁺ loses electrons and its oxidation number increases.
(4) The Pt²⁺ loses electrons and its oxidation number decreases. 2 GER
gain electrons reduction
oxidation number decrease
23 Which balanced equation represents an oxidation-reduction reaction?
(1) BaCl₂ + Na₂SO₄==>BaSO₄ + 2NaCl
(2) C+H₂O ==>CO + H₂
(3) CaCO₃==>CaO + CO₂
(4) Mg(OH)₂ + 2HNO₃==>Mg(NO₃)₂ + 2H₂O 2 look for the lone element
24 Which energy conversion occurs during the operation of a voltaic cell?
(1) Chemical energy is spontaneously converted to electrical energy.
(2) Chemical energy is converted to electrical energy only when an external power source is provided.
(3) Electrical energy is spontaneously converted to chemical energy.
(4) Electrical energy is converted to chemical energy only when an external power source is provided. 1 definition of a voltaic cell
25 An Arrhenius base yields which ion as the only negative ion in an aqueous solution?
(1) hydride ion          (3) hydronium ion
(2) hydrogen ion       (4) hydroxide ion 4 base- OH^-
26 According to one acid-base theory, a water molecule acts as an acid when the water molecule
(1) accepts an H⁺        (3) donates an H⁺
(2) accepts an OH^–     (4) donates an OH^– 3 acid donates a H⁺
27 Which list of radioisotopes contains an alpha emitter, a beta emitter, and a positron emitter?
(1) C-14, N-16, P-32
(2) Cs-137, Fr-220, Tc-99
(3) Kr-85, Ne-19, Rn-222
(4) Pu-239, Th-232, U-238 3 Table N
28 Which nuclear decay emission consists of energy, only?
(1) alpha particle   (3) gamma radiation
(2) beta particle    (4) positron 3 gamma- that is what it is
4 fusion 2 small atoms reacting to form a large one
REGENTS ONLY use hydrogen
30 The energy released by a nuclear reaction results primarily from the
(1) breaking of bonds between atoms
(2) formation of bonds between atoms
(3) conversion of mass into energy
(4) conversion of energy into mass 3 Energy comes from mass
Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

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Questions	Answer	Explanations
21 A double carbon-carbon bond is found in a molecule of (1) pentane (3) pentyne (2) pentene (4) pentanol	2	double bond-Alkenes -ene
22 Which changes occur when Pt²⁺ is reduced? (1) The Pt²⁺ gains electrons and its oxidation number increases. (2) The Pt²⁺ gains electrons and its oxidation number decreases. (3) The Pt²⁺ loses electrons and its oxidation number increases. (4) The Pt²⁺ loses electrons and its oxidation number decreases.	2	GER gain electrons reduction oxidation number decrease
23 Which balanced equation represents an oxidation-reduction reaction? (1) BaCl₂ + Na₂SO₄==>BaSO₄ + 2NaCl (2) C+H₂O ==>CO + H₂ (3) CaCO₃==>CaO + CO₂ (4) Mg(OH)₂ + 2HNO₃==>Mg(NO₃)₂ + 2H₂O	2	look for the lone element
24 Which energy conversion occurs during the operation of a voltaic cell? (1) Chemical energy is spontaneously converted to electrical energy. (2) Chemical energy is converted to electrical energy only when an external power source is provided. (3) Electrical energy is spontaneously converted to chemical energy. (4) Electrical energy is converted to chemical energy only when an external power source is provided.	1	definition of a voltaic cell
25 An Arrhenius base yields which ion as the only negative ion in an aqueous solution? (1) hydride ion (3) hydronium ion (2) hydrogen ion (4) hydroxide ion	4	base- OH^-
26 According to one acid-base theory, a water molecule acts as an acid when the water molecule (1) accepts an H⁺ (3) donates an H⁺ (2) accepts an OH^– (4) donates an OH^–	3	acid donates a H⁺
27 Which list of radioisotopes contains an alpha emitter, a beta emitter, and a positron emitter? (1) C-14, N-16, P-32 (2) Cs-137, Fr-220, Tc-99 (3) Kr-85, Ne-19, Rn-222 (4) Pu-239, Th-232, U-238	3	Table N
28 Which nuclear decay emission consists of energy, only? (1) alpha particle (3) gamma radiation (2) beta particle (4) positron	3	gamma- that is what it is
	4	fusion 2 small atoms reacting to form a large one REGENTS ONLY use hydrogen
30 The energy released by a nuclear reaction results primarily from the (1) breaking of bonds between atoms (2) formation of bonds between atoms (3) conversion of mass into energy (4) conversion of energy into mass	3	Energy comes from mass