January 2007 Chemistry Regents #11-20

Highlight to reveal answers and explanations

 

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

 

Other Regents Exams

Questions

AnswerExplanations
11 Lithium and potassium have similar chemical properties because the atoms of both elements have the same
(1) mass number
(2) atomic number
(3) number of electron shells
(4) number of valence electrons		4valence electrons determine the chemical properties
12 Which two substances are covalent compounds?
(1) C6H12O6(s) and KI(s)
(2) C6H12O(s) and HCl(g)
(3) KI(s) and NaCl(s)
(4) NaCl(s) and HCl(g)		2covalent nonmetal to nonmetal

NO METALS

13 Which substance, when dissolved in water, forms a solution that conducts an electric current?
(1) C2H5OH (3) C12H22O11
(2) C6H12O6 (4) CH3COOH		4the ionic one is an electrolyte
1splitting an atom is fission
15 Compared to a phosphorus atom, a P3 ion has
(1) more electrons and a larger radius
(2) more electrons and a smaller radius
(3) fewer electrons and a larger radius
(4) fewer electrons and a smaller radius		1more electrons and a larger radius
16 The balanced equation below represents a molecule of bromine separating into two bromine atoms.
Br2-->Br + Br
What occurs during this change?
(1) Energy is absorbed and a bond is formed.
(2) Energy is absorbed and a bond is broken.
(3) Energy is released and a bond is formed.
(4) Energy is released and a bond is broken.		2the bond broke, which requires energy (absorbs)
17 Which substance can be decomposed by chemical means?
(1) tungsten    (3) krypton
(2) antimony   (4) methane		4definition of a compound
18 Bronze contains 90 to 95 percent copper and 5 to 10 percent tin. Because these percentages can vary, bronze is classified as
(1) a compound    (3) a mixture
(2) an element      (4) a substance		3a mixture, they are not bonded together, and vary in composition
19 Compared to a 2.0 M aqueous solution of NaCl at 1 atmosphere, a 3.0 M aqueous solution of NaCl at 1 atmosphere has a
(1) lower boiling point and a higher freezing point
(2) lower boiling point and a lower freezing point
(3) higher boiling point and a higher freezing point
(4) higher boiling point and a lower freezing point		4the more concentrated

the higher the BP, and lower the FP

20 In which reaction are electrons transferred from one reactant to another reactant?
(1) 2Ca(s) + O2(g) =>2CaO(s)
(2) AgNO3(aq) + KCl(aq) =>AgCl(s) + KNO3(aq)
(3) HCl(aq) + NaOH(aq) =>NaCl(aq) + H2O(l)
(4) H3O+(aq) + OH-(aq) => 2H=O(l)		1defintion of REDOX

look for a free element (not Ion)

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

 
Back to Regents Exams