Chemistry 24 January 2013

Chemistry 24 January 2013 Questions Answer Keys

The University Of The State Of New York
Regents High School Examination
Physical Setting
Chemistry
Thursday, January 24, 2013 — 1:15 to 4:15 p.m., only

Directions (1–30): For each statement or question, record on your separate answer sheet the number of the word or expression that, of those given, best completes the statement or answers the question. Some questions may require the use of the 2011 Edition Reference Tables for Physical Setting/Chemistry.

1. Which particles have approximately the same mass?

  • (1) alpha particle and beta particle
  • (2) alpha particle and proton
  • (3) neutron and positron
  • (4) neutron and proton
Answer: (4) neutron and proton 

2. Which phrase describes an atom?

  • (1) a negatively charged nucleus surrounded by positively charged protons
  • (2) a negatively charged nucleus surrounded by positively charged electrons
  • (3) a positively charged nucleus surrounded by negatively charged protons
  • (4) a positively charged nucleus surrounded by negatively charged electrons
Answer: (4) a positively charged nucleus surrounded by negatively charged electrons 

3. An orbital is defined as a region of the most probable location of

  • (1) an electron
  • (2) a neutron
  • (3) a nucleus
  • (4) a proton
Answer: (1) an electron 

4. The bright-line spectrum of an element in the gaseous phase is produced as

  • (1) protons move from lower energy states to higher energy states
  • (2) protons move from higher energy states to lower energy states
  • (3) electrons move from lower energy states to higher energy states
  • (4) electrons move from higher energy states to lower energy states
Answer: (4) electrons move from higher energy states to lower energy states 

5. An atom of lithium-7 has an equal number of

  • (1) electrons and neutrons
  • (2) electrons and protons
  • (3) positrons and neutrons
  • (4) positrons and protons
Answer: (2) electrons and protons 

6. In which type of chemical reaction do two or more reactants combine to form one product, only?

  • (1) synthesis
  • (2) decomposition
  • (3) single replacement
  • (4) double replacement
Answer: (1) synthesis 

7. Which statement explains why neon is a Group 18 element?

  • (1) Neon is a gas at STP.
  • (2) Neon has a low melting point.
  • (3) Neon atoms have a stable valence electron configuration.
  • (4) Neon atoms have two electrons in the first shell.
Answer: (3) Neon atoms have a stable valence electron configuration. 

8. Which element has chemical properties that are most similar to the chemical properties of fluorine?

  • (1) boron
  • (2) chlorine
  • (3) neon
  • (4) oxygen
Answer: (2) chlorine 

9. What occurs as two atoms of fluorine combine to become a molecule of fluorine?

  • (1) A bond is formed as energy is absorbed.
  • (2) A bond is formed as energy is released.
  • (3) A bond is broken as energy is absorbed.
  • (4) A bond is broken as energy is released.
Answer: (2) A bond is formed as energy is released. 

10. What is the number of pairs of electrons that are shared between the nitrogen atoms in a molecule of N2?

  • (1) 1
  • (2) 2
  • (3) 3
  • (4) 6
Answer: (3) 3  

11. Which set of values represents standard pressure and standard temperature?

  • (1) 1 atm and 101.3 K
  • (2) 1 kPa and 273 K
  • (3) 101.3 kPa and 0°C
  • (4) 101.3 atm and 273°C
Answer: (3) 101.3 kPa and 0°C  

12. Which statement about one atom of an element identifies the element?

  • (1) The atom has 1 proton.
  • (2) The atom has 2 neutrons.
  • (3) The sum of the number of protons and neutrons in the atom is 3.
  • (4) The difference between the number of neutrons and protons in the atom is 1.
Answer: (1) The atom has 1 proton.  

13. A substance is classified as either an element or a

  • (1) compound
  • (2) solution
  • (3) heterogeneous mixture
  • (4) homogeneous mixture
Answer: (1) compound 

14. A solid element that is malleable, a good conductor of electricity, and reacts with oxygen is classified as a

  • (1) metal
  • (2) metalloid
  • (3) noble gas
  • (4) nonmeta
Answer: (1) metal 

15. Three forms of energy are

  • (1) chemical, exothermic, and temperature
  • (2) chemical, thermal, and electromagnetic
  • (3) electrical, nuclear, and temperature
  • (4) electrical, mechanical, and endothermic
Answer: (2) chemical, thermal, and electromagnetic 

16. What is the total amount of heat required to vaporize 1.00 gram of H2O(ℓ) at 100.°C and 1 atmosphere?

  • (1) 4.18 J
  • (2) 334 J
  • (3) 373 J
  • (4) 2260 J
Answer: (4) 2260 J 

17. What is required for a chemical reaction to occur?

  • (1) standard temperature and pressure
  • (2) a catalyst added to the reaction system
  • (3) effective collisions between reactant particles
  • (4) an equal number of moles of reactants and products
Answer: (3) effective collisions between reactant particles 

18. Which compound is soluble in water?

  • (1) PbS
  • (2) BaS
  • (3) Na2S
  • (4) Fe2S3
Answer: (3) Na2S 

19. Compared to a 26-gram sample of NaCl(s) at STP, a 52-gram sample of NaCl(s) at STP has

  • (1) a different density
  • (3) the same chemical properties
  • (2) a different gram-formula mass
  • (4) the same volume
Answer: (3) the same chemical properties 

20. A gas changes directly to a solid during

  • (1) fusion
  • (2) deposition
  • (3) saponification
  • (4) decomposition
Answer: (2) deposition 

21. The phase of a sample of a molecular substance at STP is not determined by its

  • (1) arrangement of molecules
  • (2) intermolecular forces
  • (3) number of molecules
  • (4) molecular structure
Answer: (3) number of molecules 

22. Which atom has the weakest attraction for electrons in a chemical bond?

  • (1) a boron atom
  • (2) a calcium atom
  • (3) a fluorine atom
  • (4) a nitrogen atom
Answer: (2) a calcium atom 

23. Which statement describes a chemical reaction at equilibrium?

  • (1) The products are completely consumed in the reaction.
  • (2) The reactants are completely consumed in the reaction.
  • (3) The concentrations of the products and reactants are equal.
  • (4) The concentrations of the products and reactants are constant.
Answer: (4) The concentrations of the products and reactants are constant. 

24. Which element has atoms that can bond to each other in rings and networks?

  • (1) aluminum
  • (2) carbon
  • (3) hydrogen
  • (4) oxygen
Answer: (2) carbon 

25. In an oxidation-reduction reaction, the total number of electrons lost is

  • (1) equal to the total number of electrons gained
  • (2) equal to the total number of protons gained
  • (3) less than the total number of electrons gained
  • (4) less than the total number of protons gained
Answer: (1) equal to the total number of electrons gained 

26. Which compounds are electrolytes?

  • (1) C2H5OH and H2SO4
  • (2) C2H5OH and CH4
  • (3) KOH and H2SO4
  • (4) KOH and CH4
Answer: (3) KOH and H2SO4 

27. Which compounds yield hydrogen ions as the only positive ions in an aqueous solution?

  • (1) H2CO3 and HC2H3O2
  • (2) H2CO3 and NaHCO3
  • (3) NH3 and HC2H3O2
  • (4) NH3 and NaHCO3
Answer: (1) H2CO3 and HC2H3O2 

28. Nuclei of U-238 atoms are

  • (1) stable and spontaneously absorb alpha particles
  • (2) stable and spontaneously emit alpha particles
  • (3) unstable and spontaneously absorb alpha particles
  • (4) unstable and spontaneously emit alpha particles
Answer: (4) unstable and spontaneously emit alpha particles 

29. Which nuclear emission has the greatest penetrating power?

  • (1) proton
  • (2) beta particle
  • (3) gamma radiation
  • (4) positron
Answer: (3) gamma radiation 

30. The dating of geological formations is an example of a beneficial use of

  • (1) isomers
  • (2) electrolytes
  • (3) organic compounds
  • (4) radioactive nuclides
Answer: (4) radioactive nuclides 

 

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