June 2002 Regents 21-30

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

 

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Questions

Answer Explanations
21 What is the oxidation number of chromium in K2Cr2O7?

(1) +12          (3) +3
(2) +2            (4) +6

 

4 K2Cr2O7

K 2(+1) =+2

Cr 2(x)=+12

O 7(-2)=-14

22 Which process requires an external power source?

(1) neutralization      (3) fermentation
(2) synthesis            (4) electrolysis

 

4 EXAMPLE-Electricity is required to seperate water into hydrogen
23 A substance that conducts an electrical current when dissolved in water is
called

(1) a catalyst          (3) a nonelectrolyte
(2) a metalloid        (4) an electrolyte

 

4 Definition Electrolyte

24 Which product of nuclear decay has mass but no charge?

(1) alpha particles       (3) gamma rays
(2) neutrons               (4) beta positrons

 

2 Definition-Gamma Ray

Table O

25 Given the reaction:

HCl(aq) + LiOH(aq) HOH(ℓ) + LiCl(aq)

The reaction is best described as

(1) neutralization
(2) synthesis
(3) decomposition
(4) oxidation-reduction

 

1 Neutraliztion-Acid (H+)  reacts with a base (OH-)

to produce salt and water (HOH)

26 Which ion is produced when an  is dissolved in water?

(1) H+, as the only positive ion in solution
(2) H3O+, as the only positive ion in solution
(3) OH-C, as the only negative ion in solution
(4) H- , as the only negative ion in solution

 

3 Definition- Arrhenius base
27 The change that is undergone by an atom of an element made radioactive by bombardment with high-energy protons is called

(1) natural transmutation
(2) artificial transmutation
(3) natural decay
(4) radioactive decay

2 Bombardment is artifical

transmutation- changing the number of protons (changes teh element)

28 As ice melts at standard pressure, its temperature remains at 0C until it
has completely melted. Its potential energy

(1) decreases
(2) increases
(3) remains the same

2 During a phase change potential energy changes
29 As a sample of the radioactive isotope 131I decays, its half-life

(1) decreases
(2) increases
(3) remains the same

3 HALF LIFE NEVER CHANGES
30 As an atom becomes an ion, its mass number

(1) decreases
(2) increases
(3) remains the same

3 IONS formed from a change in electrons

no effect on mass number (P and N)

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

 
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