Chemistry 20 June 2012

Chemistry 20 June 2012 Questions Answer Keys

The University Of The State Of New York
Regents High School Examination
Physical Setting
Chemistry
Wednesday, June 20, 2012 — 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. The mass of a proton is approximately equal to the mass of

  • (1) an alpha particle
  • (2) a beta particle
  • (3) a positron
  • (4) a neutron
Answer: (4) a neutron 

2. An orbital of an atom is defined as the most probable location of

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

3. What must occur when an electron in an atom returns from a higher energy state to a lower energy state?

  • (1) A specific amount of energy is released.
  • (2) A random amount of energy is released.
  • (3) The atom undergoes transmutation.
  • (4) The atom spontaneously decays.
Answer: (1) A specific amount of energy is released. 

4. Which element is a liquid at 305 K and 1.0 atmosphere?

  • (1) magnesium
  • (2) fluorine
  • (3) gallium
  • (4) iodine
Answer: (3) gallium 

5. Which list of elements consists of a metal, a metalloid, and a nonmetal?

  • (1) Li, Na, Rb
  • (2) Cr, Mo, W
  • (3) Sn, Si, C
  • (4) O, S, Te
Answer: (3) Sn, Si, C 

6. At STP, which physical property of aluminum always remains the same from sample to sample?

  • (1) mass
  • (2) density
  • (3) length
  • (4) volume
Answer: (2) density 

7. Which statement describes a chemical property of silicon?

  • (1) Silicon has a blue-gray color.
  • (2) Silicon is a brittle solid at 20.°C.
  • (3) Silicon melts at 1414°C.
  • (4) Silicon reacts with fluorine.
Answer: (4) Silicon reacts with fluorine. 

8. Which diagram represents a mixture of two different molecular forms of the same element?

Chemistry 20 June 2012

9. A compound is broken down by chemical means during

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

10. Which quantities must be conserved in all chemical reactions?

  • (1) mass, charge, density
  • (2) mass, charge, energy
  • (3) charge, volume, density
  • (4) charge, volume, energy
Answer: (2) mass, charge, energy 

11. Which phrase describes the distribution of charge and the polarity of a CH4 molecule?

  • (1) symmetrical and polar
  • (2) symmetrical and nonpolar
  • (3) asymmetrical and polar
  • (4) asymmetrical and nonpolar
Answer: (2) symmetrical and nonpolar 

12. What is the charge of the nucleus of an oxygen atom?

  • (1) 0
  • (2) –2
  • (3) +8
  • (4) +16
Answer: (3) +8 

13. Which ion has no electrons?

  • (1) H+
  • (2) Li+
  • (3) Na+
  • (4) Rb+
Answer: (1) H

14. To break a chemical bond, energy must be

  • (1) absorbed
  • (2) destroyed
  • (3) produced
  • (4) released
Answer: (1) absorbed 

15. Which Lewis electron-dot diagram represents a nitrogen atom in the ground state?

Chemistry 20 June 2012

16. What is the most likely electronegativity value for a metallic element?

  • (1) 1.3
  • (2) 2.7
  • (3) 3.4
  • (4) 4.0
Answer: (1) 1.3 

17. Which polyatomic ion has a charge of 3–?

  • (1) chromate ion
  • (2) oxalate ion
  • (3) phosphate ion
  • (4) thiocyanate ion
Answer: (3) phosphate ion 

18. Every chlorine atom has

  • (1) 7 electrons
  • (2) 17 neutrons
  • (3) a mass number of 35
  • (4) an atomic number of 17
Answer: (4) an atomic number of 17 

19. Which substance can not be broken down by a chemical change?

  • (1) ammonia
  • (2) methanol
  • (3) propane
  • (4) phosphorus
Answer: (4) phosphorus 

20. At standard pressure, which substance becomes less soluble in water as temperature increases from 10.°C to 80.°C?

  • (1) HCl
  • (2) KCl
  • (3) NaCl
  • (4) NH4Cl
Answer: (1) HCl 

21. Which type of concentration is calculated when the grams of solute is divided by the grams of the solution, and the result is multiplied by 1 000 000?

  • (1) molarity
  • (2) parts per million
  • (3) percent by mass
  • (4) percent by volume
Answer: (2) parts per million 

22. Which type of energy is associated with the random motion of atoms and molecules in a sample of air?

  • (1) chemical energy
  • (2) electrical energy
  • (3) nuclear energy
  • (4) thermal energy
Answer: (4) thermal energy 

23. The temperature of a sample of matter is a measure of the

  • (1) total kinetic energy of the particles in the sample
  • (2) total potential energy of the particles in the sample
  • (3) average potential energy of the particles in the sample
  • (4) average kinetic energy of the particles in the sample
Answer: (4) average kinetic energy of the particles in the sample 

24. Which unit is used to express the pressure of a gas?

  • (1) mole
  • (2) joule
  • (3) kelvin
  • (4) pascal
Answer: (4) pascal 

25. Which sample of matter sublimes at room temperature and standard pressure?

  • (1) Br2(ℓ)
  • (2) Cl2(g)
  • (3) CO2 (s)
  • (4) SO2(aq)
Answer: (3) CO2 (s) 

26. Given the diagram representing a closed system at constant temperature:

Chemistry 20 June 2012

Which statement describes this system at equilibrium?

  • (1) The mass of H2O(ℓ) equals the mass of H2O(g).
  • (2) The volume of H2O(ℓ) equals the volume of H2O(g).
  • (3) The number of moles of H2O(ℓ) equals the number of moles of H2O(g).
  • (4) The rate of evaporation of H2O(ℓ) equals the rate of condensation of H2O(g).
Answer: (4) The rate of evaporation of H2O(ℓ) equals the rate of condensation of H2O(g).

27. Which reaction occurs at the cathode in an electrochemical cell?

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

28. Which substance yields H(aq) as the only positive ion in an aqueous solution?

  • (1) CH3CHO
  • (2) CH3CH2OH
  • (3) CH3COOH
  • (4) CH3OCH3
Answer: (3) CH3COOH

29. Compared to the mass and the penetrating power of an alpha particle, a beta particle has

  • (1) less mass and greater penetrating power
  • (2) less mass and less penetrating power
  • (3) more mass and greater penetrating power
  • (4) more mass and less penetrating power
Answer: (1) less mass and greater penetrating power 

30. During a nuclear reaction, mass is converted into

  • (1) charge
  • (2) energy
  • (3) isomers
  • (4) volume
Answer: (2) energy

 

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