Chemistry 25 January 2018

Chemistry 25 January 2018 Questions Answer Keys

The University Of The State Of New York
Regents High School Examination
Physical Setting
Chemistry
Thursday, January 25, 2018 — 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.  Which statement describes the location of protons and neutrons in an atom of helium?

  • (1) Protons and neutrons are in the nucleus.
  • (2) Protons and neutrons are outside the nucleus.
  • (3) Protons are outside the nucleus, and neutrons are in the nucleus.
  • (4) Protons are in the nucleus, and neutrons are outside the nucleus.
Answer: (1) Protons and neutrons are in the nucleus. 

2. Given a list of atomic model descriptions:

A: electron shells outside a central nucleus
B: hard, indivisible sphere
C: mostly empty space

Which list of atomic model descriptions represents the order of historical development from the earliest to most recent?

  • (1) A, B, C
  • (2) A, C, B
  • (3) B, C, A
  • (4) B, A, C
Answer: (3) B, C, A 

3. Which list represents the classification of the elements nitrogen, neon, magnesium, and silicon, respectively?

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

4. In the ground state, all atoms of Group 15 elements have the same number of

  • (1) valence electrons
  • (2) electron shells
  • (3) neutrons
  • (4) protons
Answer: (1) valence electrons 

5. What is the chemical formula for ammonium sulfide?

  • (1) (NH4)2S
  • (2) (NH4)2SO3
  • (3) (NH4)2SO4
  • (4) (NH4)2S2O3
Answer: (1) (NH4)2S 

6. Which formula is an empirical formula?

  • (1) N2O4
  • (2) NH3
  • (3) C3H6
  • (4) P4O10
Answer: (2) NH3 

7. Chemical properties can be used to

  • (1) determine the temperature of a substance
  • (2) determine the density of a substance
  • (3) differentiate between two compounds
  • (4) differentiate between two neutrons
Answer: (3) differentiate between two compounds 

8. Ice, H2O(s), is classified as

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

9. Which phrase describes the molecular polarity and distribution of charge in a molecule of carbon dioxide, CO2?

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

10. Which element tends not to react with other elements?

  • (1) helium
  • (2) hydrogen
  • (3) phosphorus
  • (4) potassium
Answer: (1) helium 

11. Given the equation representing a reaction:

O O → O2

Which statement describes the changes that occur as the oxygen molecule is produced?

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

12. Which term represents the strength of the attraction an atom has for the electrons in a chemical bond?

  • (1) electrical conductivity
  • (2) electronegativity
  • (3) first ionization energy
  • (4) specific heat capacity
Answer: (2) electronegativity. 

13. Compared to a 15-gram sample of Cu(s) at 25°C, a 25-gram sample of Cu(s) at 25°C has

  • (1) the same density and the same chemical properties
  • (2) the same density and different chemical properties
  • (3) a different density and the same chemical properties
  • (4) a different density and different chemical properties
Answer: (1) the same density and the same chemical properties 

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

  • (1) ammonia
  • (2) ethanol
  • (3) tungsten
  • (4) water
Answer: (3) tungsten 

15. The kinetic molecular theory states that all particles of an ideal gas are

  • (1) colliding without transferring energy
  • (2) in random, constant, straight-line motion
  • (3) arranged in a regular geometric pattern
  • (4) separated by small distances relative to their size
Answer: (2) in random, constant, straight-line motion 

16. Which sample of gas at STP has the same number of molecules as 6 liters of Cl2(g) at STP?

  • (1) 3 liters of O2 (g)
  • (2) 6 liters of N2 (g)
  • (3) 3 moles of O2 (g)
  • (4) 6 moles of N2(g)
Answer: (2) 6 liters of N2 (g) 

17. A chemical reaction is most likely to occur when the colliding particles have the proper

  • (1) energy and orientation
  • (2) solubility and density
  • (3) ionic radii and mass
  • (4) atomic radii and volume
Answer: (1) energy and orientation 

18. The energy absorbed and the energy released during a chemical reaction are best represented by a

  • (1) cooling curve
  • (2) heating curve
  • (3) kinetic energy diagram
  • (4) potential energy diagram
Answer: (4) potential energy diagram 

19. A catalyst increases the rate of a chemical reaction by

  • (1) providing an alternate reaction pathway
  • (2) providing the required heat of reaction
  • (3) increasing the potential energy of the products
  • (4) increasing the activation energy of the reaction
Answer: (1) providing an alternate reaction pathway 

20. Which formula represents an alkyne?

  • (1) CnHn
  • (2) C2nHn
  • (3) CnH2n + 2
  • (4) CnH2n2
Answer: (4) CnH2n2 

21. Which process involves the transfer of electrons?

  • (1) double replacement
  • (2) neutralization
  • (3) oxidation-reduction
  • (4) sublimation
Answer: (3) oxidation-reduction 

22. Which change occurs at the anode in an operating electrochemical cell?

  • (1) gain of protons
  • (2) gain of electrons
  • (3) loss of protons
  • (4) loss of electrons
Answer: (4) loss of electrons 

23. Which device requires electrical energy to produce a chemical change?

  • (1) electrolytic cell
  • (2) salt bridge
  • (3) voltaic cell
  • (4) voltmeter
Answer: (1) electrolytic cell 

24. Which substance is an Arrhenius acid?

  • (1) HBr
  • (2) NaBr
  • (3) NaOH
  • (4) NH3
Answer: (1) HBr 

25. Which laboratory process is used to determine the concentration of one solution by using a volume of another solution of known concentration?

  • (1) crystallization
  • (2) distillation
  • (3) filtration
  • (4) titration
Answer: (4) titration 

26. Which type of reaction occurs when H(aq) reacts with OH+(aq)?

  • (1) combustion
  • (2) decomposition
  • (3) fermentation
  • (4) neutralization
Answer: (4) neutralization 

27. According to one acid-base theory, a molecule acts as an acid when the molecule

  • (1) accepts an H+
  • (2) accepts an OH
  • (3) donates an H+
  • (4) donates an OH
Answer: (3) donates an H+ 

28. In which type of reaction can an atom of one element be converted to an atom of another element?

  • (1) addition
  • (2) reduction
  • (3) substitution
  • (4) transmutation
Answer: (4) transmutation 

29. An unstable nucleus spontaneously releases a positron. This is an example of

  • (1) radioactive decay
  • (2) nuclear fusion
  • (3) chemical decomposition
  • (4) thermal conductivity
Answer: (1) radioactive decay 

30. Which phrase describes a risk associated with producing energy in a nuclear power plant?

  • (1) depletion of atmospheric hydrogen (H2)
  • (2) depletion of atmospheric carbon dioxide (CO2)
  • (3) production of wastes needing long-term storage
  • (4) production of wastes that cool surrounding water supplies
Answer: (3) production of wastes needing long-term storage 

 

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