Chemistry 20 June 2018

Chemistry 20 June 2018 Questions Answer Keys

The University Of The State Of New York
Regents High School Examination
Physical Setting
Chemistry
Wednesday, June 20, 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 charge and location of an electron in an atom?

  • (1) An electron has a positive charge and is located outside the nucleus.
  • (2) An electron has a positive charge and is located in the nucleus.
  • (3) An electron has a negative charge and is located outside the nucleus.
  • (4) An electron has a negative charge and is located in the nucleus.
Answer: (3) An electron has a negative charge and is located outside the nucleus.

2. Which statement explains why a xenon atom is electrically neutral?

  • (1) The atom has fewer neutrons than electrons.
  • (2) The atom has more protons than electrons.
  • (3) The atom has the same number of neutrons and electrons.
  • (4) The atom has the same number of protons and electrons.
Answer: (4) The atom has the same number of protons and electrons.

3. If two atoms are isotopes of the same element, the atoms must have

  • (1) the same number of protons and the same number of neutrons
  • (2) the same number of protons and a different number of neutrons
  • (3) a different number of protons and the same number of neutrons
  • (4) a different number of protons and a different number of neutrons
Answer: (2) the same number of protons and a different number of neutrons

4. Which electrons in a calcium atom in the ground state have the greatest effect on the chemical properties of calcium?

  • (1) the two electrons in the first shell
  • (2) the two electrons in the fourth shell
  • (3) the eight electrons in the second shell
  • (4) the eight electrons in the third shell
Answer: (2) the two electrons in the fourth shell

5. The weighted average of the atomic masses of the naturally occuring isotopes of an element is the

  • (1) atomic mass of the element
  • (2) atomic number of the element
  • (3) mass number of each isotope
  • (4) formula mass of each isotope
Answer: (1) atomic mass of the element

6. Which element is classified as a metalloid?

  • (1) Cr
  • (2) Cs
  • (3) Sc
  • (4) Si
Answer: (4) Si

7. Which statement describes a chemical property of iron?

  • (1) Iron oxidizes.
  • (2) Iron is a solid at STP.
  • (3) Iron melts.
  • (4) Iron is attracted to a magnet.
Answer: (1) Iron oxidizes.

8. Graphite and diamond are two forms of the same element in the solid phase that differ in their

  • (1) atomic numbers
  • (2) crystal structures
  • (3) electronegativities
  • (4) empirical formulas
Answer: (2) crystal structures

9. Which ion has the largest radius?

  • (1) Br
  • (2) Cl
  • (3) F
  • (4) I
Answer: (4) I

10. Carbon monoxide and carbon dioxide have

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

11. Based on Table S, which group on the Periodic Table has the element with the highest electronegativity?

  • (1) Group 1
  • (2) Group 2
  • (3) Group 17
  • (4) Group 18
Answer: (3) Group 17

12. What is represented by the chemical formula PbCl2(s)?

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

13. What is the vapor pressure of propanone at 50.°C?

  • (1) 37 kPa
  • (2) 50. kPa
  • (3) 83 kPa
  • (4) 101 kPa
Answer: (3) 83 kPa

14. Which statement describes the charge distribution and the polarity of a CH4 molecule?

  • (1) The charge distribution is symmetrical and the molecule is nonpolar.
  • (2) The charge distribution is asymmetrical and the molecule is nonpolar.
  • (3) The charge distribution is symmetrical and the molecule is polar.
  • (4) The charge distribution is asymmetrical and the molecule is polar.
Answer: (3) 83 kPa1) The charge distribution is symmetrical and the molecule is nonpolar.

15. In a laboratory investigation, a student separates colored compounds obtained from a mixture of crushed spinach leaves and water by using paper chromatography. The colored compounds separate because of differences in

  • (1) molecular polarity
  • (2) malleability
  • (3) boiling point
  • (4) electrical conductivity
Answer: (1) molecular polarity

16. Which phrase describes the motion and attractive forces of ideal gas particles?

  • (1) random straight-line motion and no attractive forces
  • (2) random straight-line motion and strong attractive forces
  • (3) random curved-line motion and no attractive forces
  • (4) random curved-line motion and strong attractive forces
Answer: (1) random straight-line motion and no attractive forces

17. At which temperature will Hg() and Hg(s) reach equilibrium in a closed system at 1.0 atmosphere?

  • (1) 234 K
  • (2) 273 K
  • (3) 373 K
  • (4) 630. K
Answer: (1) 234 K

18. A molecule of any organic compound has at least one

  • (1) ionic bond
  • (2) double bond
  • (3) oxygen atom
  • (4) carbon atom
Answer: (4) carbon atom

19. A chemical reaction occurs when reactant particles

  • (1) are separated by great distances
  • (2) have no attractive forces between them
  • (3) collide with proper energy and proper orientation
  • (4) convert chemical energy into nuclear energy
Answer: (3) collide with proper energy and proper orientation

20. Systems in nature tend to undergo changes toward

  • (1) lower energy and lower entropy
  • (2) lower energy and higher entropy
  • (3) higher energy and lower entropy
  • (4) higher energy and higher entropy
Answer: (2) lower energy and higher entropy 

21. Which formula can represent an alkyne?

  • (1) C2H4
  • (2) C2H6
  • (3) C3H4
  • (4) C3H6
Answer: (3) C3H4

22. Given the formula representing a compound:

Which formula represents an isomer of this compound?

Answer: (2)  

23. Which energy conversion occurs in an operating voltaic cell?

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

24. Which process requires energy to decompose a substance?

  • (1) electrolysis
  • (2) neutralization
  • (3) sublimation
  • (4) synthesis
Answer: (1) electrolysis 

25. The concentration of which ion is increased when LiOH is dissolved in water?

  • (1) hydroxide ion
  • (2) hydrogen ion
  • (3) hydronium ion
  • (4) halide ion
Answer: (1) hydroxide ion

26. Which equation represents neutralization?

  • (1) 6Li(s) + N2(g) → 2Li3N(s)
  • (2) 2Mg(s) + O2(g) → 2MgO(s)
  • (3) 2KOH(aq) + H2SO4(aq) →
    K2SO4(aq) + 2H2O(ℓ)
  • (4) Pb(NO3)2(aq) + K2CrO4(aq) →
    2KNO3(aq) + PbCrO4(s)
Answer: (3) 2KOH(aq) + H2SO4(aq) →
K2SO4(aq) + 2H2O(ℓ)

27. The stability of an isotope is related to its ratio of

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

28. Which particle has the least mass?

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

29. The energy released during a nuclear reaction is a result of

  • (1) breaking chemical bonds
  • (2) forming chemical bonds
  • (3) mass being converted to energy
  • (4) energy being converted to mass
Answer: (3) mass being converted to energy 

30. The use of uranium-238 to determine the age of a geological formation is a beneficial use of

  • (1) nuclear fusion
  • (2) nuclear fission
  • (3) radioactive isomers
  • (4) radioactive isotopes
Answer: (4) radioactive isotopes 

 

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