January 2004 Regents #41-50

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

Answer Explanations
41 What is the Molarity of a solution containing 20 grams of NaOH in 500 milliliters of solution?
(1) 1 M      (3) 0.04 M
(2) 2 M      (4) 0.5 M
1 mole/Liters  

moles=20g/40g=0.5mol

500mL is 0.5L

M=0.5mol/0.5L= 1M

4 indirect relationship
43 Given the equation:
C2H6 + Cl2  --> C2H5Cl + HCl
This reaction is best described as
(1) addition involving a saturated hydrocarbon
(2) addition involving an unsaturated hydrocarbon
(3) substitution involving a saturated hydrocarbon
(4) substitution involving an unsaturated hydrocarbon
3 Substitution Saturated
2 Cu2+ is reduced to Cu on the key

 

Red Cat

45 A student neutralized 16.4 milliliters of HCl by adding 12.7 milliliters of 0.620 M KOH. What was the molarity of the HCl acid?
(1) 0.168 M      (3) 0.620 M
(2) 0.480 M      (4) 0.801 M
2 MV=MV

M(16.4mL)= (0.620M)(12.7mL)

M=0.480M

46 Nuclear fusion differs from nuclear fission because nuclear fusion reactions
(1) form heavier isotopes from lighter isotopes
(2) form lighter isotopes from heavier isotopes
(3) convert mass to energy
(4) convert energy to mass
2  H + H--> He       fusion (light atoms)

U + n--> Ba + Kr +3n   fission (heavy atoms)

47 After 32 days, 5 milligrams of an 80-milligram sample of a radioactive isotope remains unchanged. What is the half-life of this element?
(1) 8 days      (3) 16 days
(2) 2 days      (4) 4 days
1 80-->40-->20-->10-->5   4 half lives

32days/4 = 8 days per half life

48 Which electron configuration represents an
atom of chlorine in an excited state?
(1) 2𤾉           (3) 2𤾈1
(2) 2𤾊           (4) 2𤾉1
3 17 electrons with 1 promoted
49 As each successive element in Group 15 of the Periodic Table is considered in order of increasing atomic number, the atomic radius
(1) decreases
(2) increases
(3) remains the same
2 See table S, or atomic snowman

o

0

O

2 adding water causes more KNO3 to dissolve

so solid becomes aqueous, entropy increases

 

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

 
Back to Regents Exams
 

web stats analysis