Chemistry 13 August 2015

Chemistry 13 August 2015 Questions Answer Keys

The University Of The State Of New York
Regents High School Examination
Physical Setting
Chemistry
Thursday, August 13, 2015 — 12:30 to 3:30 p.m., only

Directions (1–30): For each statement or question, select the word or expression that, of those given, best completes the statement or answers the question. Record your answer on the separate answer sheet in accordance with the directions on the front page of this booklet. Some questions may require the use of the 2011 Edition Reference Tables for Physical Setting/Chemistry

1. Which subatomic particles are paired with their charges?

  • (1) electron–positive, neutron–negative, proton–neutral
  • (2) electron–negative, neutron–neutral, proton–positive
  • (3) electron–negative, neutron–positive, proton–neutral
  • (4) electron–neutral, neutron–positive, proton–negative
Answer: (2) electron–negative, neutron–neutral, proton–positive 

2. In the ground state, an atom of which element has two valence electrons?

  • (1) Cr
  • (2) Cu
  • (3) Ni
  • (4) Se
Answer: (3) Ni 

3. The atoms in a sample of an element are in excited states. A bright-line spectrum is produced when these atoms

  • (1) absorb energy
  • (2) absorb positrons
  • (3) emit energy
  • (4) emit positrons
Answer: (3) emit energy 

4. Which statement describes a concept included in the wave-mechanical model of the atom?

  • (1) Positrons are located in shells outside the nucleus.
  • (2) Neutrons are located in shells outside the nucleus.
  • (3) Protons are located in orbitals outside the nucleus.
  • (4) Electrons are located in orbitals outside the nucleus.
Answer: (4) Electrons are located in orbitals outside the nucleus. 

5. All elements on the modern Periodic Table are arranged in order of increasing

  • (1) atomic mass
  • (2) molar mass
  • (3) number of neutrons per atom
  • (4) number of protons per atom
Answer: (4) number of protons per atom 

6. At STP, which substance is a noble gas?

  • (1) ammonia
  • (2) chlorine
  • (3) neon
  • (4) nitrogen
Answer: (3) neon 

7. At STP, oxygen exists in two forms, O2(g) and O3(g). These two forms of oxygen have

  • (1) different molecular structures and different properties
  • (2) different molecular structures and the same properties
  • (3) the same molecular structure and different properties
  • (4) the same molecular structure and the same properties
Answer: (1) different molecular structures and different properties 

8.  Which statement describes a chemical property of sodium?

  • (1) Sodium has a melting point of 371 K.
  • (2) Sodium has a molar mass of 23 grams.
  • (3) Sodium can conduct electricity in the liquid phase.
  • (4) Sodium can combine with chlorine to produce a salt.
Answer: (4) Sodium can combine with chlorine to produce a salt. 

9. Which term identifies a type of chemical reaction?

  • (1) decomposition
  • (2) distillation
  • (3) sublimation
  • (4) vaporization
Answer: (1) decomposition. 

10. Based on Table S, an atom of which element has the weakest attraction for electrons in a chemical bond?

  • (1) polonium
  • (2) sulfur
  • (3) selenium
  • (4) tellurium
Answer: (1) polonium

11. Given the balanced equation:

F2 energy → F + F

Which statement describes what occurs during this reaction?

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

12. Which atoms will bond when valence electrons are transferred from one atom to the other?

  • (1) O and Se
  • (2) O and Sr
  • (3) O and H
  • (4) O and P
Answer: (2) O and Sr

13. Which sample of matter is a mixture?

  • (1) Br2(ℓ)
  • (2) K(s)
  • (3) KBr(s)
  • (4) KBr(aq)
Answer: (4) KBr(aq)r

14. According to kinetic molecular theory, collisions between gas particles in a sample of an ideal gas

  • (1) increase the energy content of the gas sample
  • (2) produce strong attractive forces between the gas particles
  • (3) result in a net loss of energy by the gas sample
  • (4) transfer energy between the gas particles
Answer: (4) transfer energy between the gas particles

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

  • (1) ethane
  • (2) propanone
  • (3) silicon
  • (4) water
Answer: (3) silicon

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

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

17. Under which conditions of temperature and pressure does a real gas behave most like an ideal gas?

  • (1) 37 K and 1 atm
  • (2) 37 K and 8 atm
  • (3) 347 K and 1 atm
  • (4) 347 K and 8 atm
Answer: (3) 347 K and 1 atm

18. The ratio of chromium to iron to carbon varies among the different types of stainless steel. Therefore, stainless steel is classified as

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

19. Which statement explains why increasing the temperature increases the rate of a chemical reaction, while other conditions remain the same?

  • (1) The reacting particles have less energy and collide less frequently.
  • (2) The reacting particles have less energy and collide more frequently.
  • (3) The reacting particles have more energy and collide less frequently.
  • (4) The reacting particles have more energy and collide more frequently.
Answer: (4) The reacting particles have more energy and collide more frequently.

20. An open flask is half filled with water at 25°C. Phase equilibrium can be reached after

  • (1) more water is added to the flask
  • (2) the flask is stoppered
  • (3) the temperature is decreased to 15°C
  • (4) the temperature is increased to 35°C
Answer: (2) the flask is stoppered

21.Which formula represents an unsaturated organic compound?

  • (1) CH4
  • (2) C2H4
  • (3) C3H8
  • (4) C4H10
Answer: (2) the flask is stoppered

22. All isomers of octane have the same

  • (1) molecular formula
  • (2) structural formula
  • (3) physical properties
  • (4) IUPAC name
Answer: (1) molecular formula

23. Which formula represents a hydrocarbon?

  • (1) CH3I
  • (2) CH3NH2
  • (3) CH3CH3
  • (4) CH3OH
Answer: (3) CH3CH3

24. In a redox reaction, the number of electrons lost is equal to the number of

  • (1) protons lost
  • (2) neutrons lost
  • (3) neutrons gained
  • (4) electrons gained
  • (4) CH3OH
Answer: (4) electrons gained 

25. At which electrode does oxidation occur in a voltaic cell and in an electrolytic cell?

  • (1) the anode in a voltaic cell and the cathode in an electrolytic cell
  • (2) the cathode in a voltaic cell and the anode in an electrolytic cell
  • (3) the anode in both a voltaic cell and an electrolytic cell
  • (4) the cathode in both a voltaic cell and an electrolytic cell
Answer: (3) the anode in both a voltaic cell and an electrolytic cell

26. Based on the Arrhenius theory, when potassium hydroxide dissolves in water, the only negative ion in the aqueous solution is

  • (1) O2– (aq)
  • (2) OH2– (aq)
  • (3) H (aq)
  • (4) OH (aq)
Answer: (4) OH (aq)

27. Compared to distilled water, an aqueous salt solution has

  • (1) better electrical conductivity
  • (2) poorer electrical conductivity
  • (3) a lower boiling point at standard pressure
  • (4) a higher freezing point at standard pressure
Answer: (1) better electrical conductivity 

28. According to one acid-base theory, water can act as a base because a water molecule can

  • (1) donate an H+ ion
  • (2) accept an H ion
  • (3) donate an H+ ion
  • (4) accept an H ion
Answer: (2) accept an H iony 

29. Compared to the half-life and decay mode of the nuclide 90Sr, the nuclide 226Ra has

  • (1) a longer half-life and the same decay mode
  • (2) a longer half-life and a different decay mode
  • (3) a shorter half-life and the same decay mode
  • (4) a shorter half-life and a different decay mode
Answer: (2) a longer half-life and a different decay mode 

30. Which net change occurs in a nuclear fusion reaction?

  • (1) Ionic bonds are broken.
  • (3) Energy is converted to mass.
  • (2) Ionic bonds are formed.
  • (4) Mass is converted to energy.
Answer: (4) Mass is converted to energy.

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