2004 August Chemistry Regents Exam #21-30

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

 

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21 Even though the process is endothermic, snow can sublime. Which tendency in nature accounts for this phase change?

(1) a tendency toward greater entropy

(2) a tendency toward greater energy

(3) a tendency toward less entropy

(4) a tendency toward less energy

1 entropy increase as solids become a gas

22 What is the IUPAC name of the compound with

the structural formula shown below?

(1) 2-pentene     (3) 2-pentyne

(2) 3-pentene     (4) 3-pentyne

1 2-pentene, the double bond is on the second carbon from the right

-ene is used because there is a double bond

23 Molecules of 1-bromopropane and 2-bromopropane differ in

(1) molecular formula

(2) structural formula

(3) number of carbon atoms per molecule

(4) number of bromine atoms per molecule

 

2 different structures

24 Which half-reaction correctly represents reduction?

(1) Ag --> Ag+ + e– 

(2) F2 -->  2 F + 2e– 

(3) Au3+ + 3e-->  Au

(4) Fe2+ + e -->  Fe3+

3 charge decreases the electrons go on the more positive side

25 In a redox reaction, how does the total number of electrons lost by the oxidized substance compare to the total number of electrons gained by the reduced substance?

(1) The number lost is always greater than the number gained.

(2) The number lost is always equal to the number gained.

(3) The number lost is sometimes equal to the number gained.

(4) The number lost is sometimes less than the number gained.

2 lost always equals gain

26 Which reaction is an example of an oxidation reduction reaction?

(1) AgNO3 + KI -->  AgI + KNO3

(2) Cu + 2 AgNO3 -->  Cu(NO3)2 + 2 Ag

(3) 2 KOH + H2SO4 -->  K2SO4 + 2 H2O

(4) Ba(OH)2 + 2 HCl -->  BaCl2 + 2 H2O

2 look for the charge change

***find the reaction involving a free element

27 Which compound is an Arrhenius base?

(1) CH3OH     (3) LiOH

(2) CO2             (4) NO2

3 Bases have OH-

 

NOT CH3OH 

28 The only positive ion found in an aqueous solution of sulfuric acid is the

(1) hydroxide ion      (3) sulfite ion

(2) hydronium ion     (4) sulfate ion

2 Acid  H+  or H3O+ (hydronium)

29 Which process uses a volume of solution of known concentration to determine the concentration of another solution?

(1) distillation          (3) transmutation

(2) substitution        (4) titration

4 definition of titration

Note Acid Base section, look for this one

30 Which pH change represents a hundredfold increase in the concentration of H3O+?

(1) pH 5 to pH 7         (3) pH 3 to pH 1

(2) pH 13 to pH 14     (4) pH 4 to pH 3

3 count the number of zeros in 100

more acidic the pH decrease by 2

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

 
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