Regents Chemistry Exam Explanations June 2006

June 2006 Chemistry Regents #21-30

Highlight to reveal answers and explanations

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

Questions
Answer Explanations
21 Which factors must be equal in a reversible chemical reaction at equilibrium?
(1) the activation energies of the forward and reverse reactions
(2) the rates of the forward and reverse reactions
(3) the concentrations of the reactants and products
(4) the potential energies of the reactants and products 2 equilibrium
concentration constant
rates are equal
22 The compounds CH₃OCH₃ and CH₃CH₂OH are isomers of each other. These two compounds must have the same
(1) density      (3) melting point
(2) reactivity   (4) molecular formula 4 same formula different structure
23 Which balanced equation represents a redox reaction?
(1) AgNO₃+ NaCl ==>AgCl + NaNO₃
(2) BaCl₂ + K₂CO₃ ==> BaCO₃ + 2KCl
(3) CuO + CO==> Cu + CO₂
(4) HCl + KOH ==> KCl + H₂O 3 look for the free element
24 Which process occurs at the anode in an electrochemical cell?
(1) the loss of protons
(2) the loss of electrons
(3) the gain of protons
(4) the gain of electrons 2 An OX, LEO lose electrons
Red Cat, GER gain electrons
25 Which substance is an electrolyte?
(1) CH₃OH     (3) H₂O
(2) C₆H₁₂O₆   (4) KOH 4 electrolytes are acids bases and salts
KOH is a base
26 Which ion is the only negative ion present in an aqueous solution of an Arrhenius base?
(1) hydride ion     (3) hydronium ion
(2) hydrogen ion (4) hydroxide ion 4 OH^- hydroxide
27 According to Reference Table N, which pair of isotopes spontaneously decays?
(1) C-12 and N-14   (3) C-14 and N-14
(2) C-12 and N-16   (4) C-14 and N-16 4 the ones actually on that Table
1 Table N
it is an alpha decay
29 Which type of reaction converts one element to another element?
(1) neutralization     (3) substitution
(2) polymerization (4) transmutation 4 definition of transmutation
1 alpha is the heaviest
Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

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Questions	Answer	Explanations
21 Which factors must be equal in a reversible chemical reaction at equilibrium? (1) the activation energies of the forward and reverse reactions (2) the rates of the forward and reverse reactions (3) the concentrations of the reactants and products (4) the potential energies of the reactants and products	2	equilibrium concentration constant rates are equal
22 The compounds CH₃OCH₃ and CH₃CH₂OH are isomers of each other. These two compounds must have the same (1) density (3) melting point (2) reactivity (4) molecular formula	4	same formula different structure
23 Which balanced equation represents a redox reaction? (1) AgNO₃+ NaCl ==>AgCl + NaNO₃ (2) BaCl₂ + K₂CO₃ ==> BaCO₃ + 2KCl (3) CuO + CO==> Cu + CO₂ (4) HCl + KOH ==> KCl + H₂O	3	look for the free element
24 Which process occurs at the anode in an electrochemical cell? (1) the loss of protons (2) the loss of electrons (3) the gain of protons (4) the gain of electrons	2	An OX, LEO lose electrons Red Cat, GER gain electrons
25 Which substance is an electrolyte? (1) CH₃OH (3) H₂O (2) C₆H₁₂O₆ (4) KOH	4	electrolytes are acids bases and salts KOH is a base
26 Which ion is the only negative ion present in an aqueous solution of an Arrhenius base? (1) hydride ion (3) hydronium ion (2) hydrogen ion (4) hydroxide ion	4	OH^- hydroxide
27 According to Reference Table N, which pair of isotopes spontaneously decays? (1) C-12 and N-14 (3) C-14 and N-14 (2) C-12 and N-16 (4) C-14 and N-16	4	the ones actually on that Table
	1	Table N it is an alpha decay
29 Which type of reaction converts one element to another element? (1) neutralization (3) substitution (2) polymerization (4) transmutation	4	definition of transmutation
	1	alpha is the heaviest