Chemistry 18 June 2013

Chemistry 18 June 2013 Questions Answer Keys

The University Of The State Of New York
Regents High School Examination
Physical Setting
Chemistry
Tuesday, June 18, 2013 — 9:15 a.m. to 12:15 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. According to the wave-mechanical model of the atom, an orbital is a region of the most probable location of

  • (1) an alpha particle
  • (2) a gamma ray
  • (3) an electron
  • (4) a proton
Answer: (3) an electron 

2. Which particles have approximately the same mass?

  • (1) an electron and an alpha particle
  • (2) an electron and a proton
  • (3) a neutron and an alpha particle
  • (4) a neutron and a proton
Answer: (4) a neutron and a proton 

3. During a flame test, a lithium salt produces a characteristic red flame. This red color is produced when electrons in excited lithium atoms

  • (1) are lost by the atoms
  • (2) are gained by the atoms
  • (3) return to lower energy states within the atoms
  • (4) move to higher energy states within the atoms
Answer: (3) return to lower energy states within the atoms 

4. Compared to the energy and charge of the electrons in the first shell of a Be atom, the electrons in the second shell of this atom have

  • (1) less energy and the same charge
  • (2) less energy and a different charge
  • (3) more energy and the same charge
  • (4) more energy and a different charge
Answer: (3) more energy and the same charge 

5. Which quantity can vary among atoms of the same element?

  • (1) mass number
  • (2) atomic number
  • (3) number of protons
  • (4) number of electrons
Answer: (1) mass number 

6. Which substances have atoms of the same element but different molecular structures?

  • (1) He(g) and Ne(g)
  • (2) O2(g) and O3(g)
  • (3) K(s) and Na(s)
  • (4) P4(s) and S8(s)
Answer: (2) O2(g) and O3(g) 

7. An atom that has 13 protons and 15 neutrons is an isotope of the element

  • (1) nickel
  • (2) silicon
  • (3) aluminum
  • (4) phosphorus
Answer: (3) aluminum

8. Which elements have the most similar chemical properties?

  • (1) Si, As, and Te
  • (2) N2, O2, and F2
  • (3) Mg, Sr, and Ba
  • (4) Ca, Cs, and Cu
Answer: (3) Mg, Sr, and Ba

9. Which list includes three types of chemical formulas for organic compounds?

  • (1) covalent, metallic, isotopic
  • (2) covalent, metallic, molecular
  • (3) empirical, structural, isotopic
  • (4) empirical, structural, molecular
Answer: (4) empirical, structural, molecular 

10. In a bond between an atom of carbon and an atom of fluorine, the fluorine atom has a

  • (1) weaker attraction for electrons
  • (2) stronger attraction for electrons
  • (3) smaller number of first-shell electrons
  • (4) larger number of first-shell electrons
Answer: (2) stronger attraction for electrons

11. A sample of CO2(s) and a sample of CO2(g) differ in their

  • (1) chemical compositions
  • (2) empirical formulas
  • (3) molecular structures
  • (4) physical properties
Answer: (4) physical properties

12. Which statement defines the temperature of a sample of matter?

  • (1) Temperature is a measure of the total electromagnetic energy of the particles.
  • (2) Temperature is a measure of the total thermal energy of the particles.
  • (3) Temperature is a measure of the average potential energy of the particles.
  • (4) Temperature is a measure of the average kinetic energy of the particles.
Answer: (4) Temperature is a measure of the average kinetic energy of the particles.

13. For a chemical reaction, the difference between the potential energy of the products and the potential energy of the reactants is equal to the

  • (1) heat of fusion
  • (2) heat of reaction
  • (3) activation energy of the forward reaction
  • (4) activation energy of the reverse reaction
Answer: (2) heat of reaction

14. Which equation represents sublimation?

  • (1) Hg(ℓ) → Hg(s)
  • (2) H2O(s) → H2O(g)
  • (3) NH3(g) → NH3(ℓ)
  • (4) CH4(ℓ) → CH4(g)
Answer: (2) H2O(s) → H2O(g)

15. Which statement describes the particles of an ideal gas, based on the kinetic molecular theory?

  • (1) The motion of the gas particles is orderly and circular.
  • (2) The gas particles have no attractive forces between them.
  • (3) The gas particles are larger than the distances separating them.
  • (4) As the gas particles collide, the total energy of the system decreases.
Answer: (2) The gas particles have no attractive forces between them. 

16. Two grams of potassium chloride are completely dissolved in a sample of water in a beaker. This solution is classified as

  • (1) an element
  • (2) a compound
  • (3) a homogeneous mixture
  • (4) a heterogeneous mixture
Answer: (3) a homogeneous mixture

17. Which compound has the strongest hydrogen bonding between its molecules?

  • (1) HBr
  • (2) HCl
  • (3) HF
  • (4) HI
Answer: (3) HF

18. Powdered sulfur is yellow, and powdered iron is gray. When powdered sulfur and powdered iron are mixed at 20°C, the powdered iron

  • (1) becomes yellow
  • (2) becomes a liquid
  • (3) remains ionic
  • (4) remains magnetic
Answer: (4) remains magnetic

19. An effective collision between reactant particles requires the particles to have the proper

  • (1) charge and mass
  • (2) charge and orientation
  • (3) energy and mass
  • (4) energy and orientation
Answer: (4) energy and orientation

20. Which term is defined as a measure of the disorder of a system?

  • (1) heat
  • (2) entropy
  • (3) kinetic energy
  • (4) activation energy
Answer: (2) entropy

21. Which process is used to determine the concentration of an acid?

  • (1) chromatography
  • (2) distillation
  • (3) electrolysis
  • (4) titration
Answer: (4) titration

22. The compounds CH3OCH3 and CH3CH2OH have different functional groups. Therefore, these compounds have different

  • (1) chemical properties
  • (2) gram-formula masses
  • (3) percent compositions by mass
  • (4) numbers of atoms per molecule
Answer: (1) chemical properties

23. Which term identifies the half-reaction that occurs at the anode of an operating electrochemical cell?

  • (1) oxidation
  • (2) reduction
  • (3) neutralization
  • (4) transmutation
Answer: (1) oxidation 

24. During the operation of a voltaic cell, the cell produces

  • (1) electrical energy spontaneously
  • (2) chemical energy spontaneously
  • (3) electrical energy nonspontaneously
  • (4) chemical energy nonspontaneously
Answer: (1) electrical energy spontaneously

25. In which type of chemical reaction are electrons transferred?

  • (1) organic addition
  • (2) oxidation-reduction
  • (3) double replacement
  • (4) acid-base neutralization
Answer: (2) oxidation-reduction

26. A substance that dissolves in water and produces hydronium ions as the only positive ions in the solution is classified as

  • (1) an alcohol
  • (2) an acid
  • (3) a base
  • (4) a salt
Answer: (2) an acid

27. According to one acid-base theory, a base is an

  • (1) H+ acceptor
  • (2) H+ donor
  • (3) Na+ acceptor
  • (4) Na+ donor
Answer: (1) H+ acceptor

28. Which compound is an electrolyte?

  • (1) CCl4
  • (2) CH3OH
  • (3) C6H12O6
  • (4) Ca(OH)2
Answer: (4) Ca(OH)2 

29. Which term identifies a type of nuclear reaction?

  • (1) fermentation
  • (2) deposition
  • (3) reduction
  • (4) fission
Answer: (4) fission 

30. Which radioisotopes have the same decay mode and have half-lives greater than 1 hour?

  • (1) Au-198 and N-16
  • (2) Ca-37 and Fe-53
  • (3) I-131 and P-32
  • (4) Tc-99 and U-233
Answer: (3) I-131 and P-32

 

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