Chemistry 20 June 2017

Chemistry 20 June 2017 Questions Answer Keys

The University Of The State Of New York
Regents High School Examination
Physical Setting
Chemistry
Tuesday, June 20, 2017 — 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 structure of an atom?

  • (1) The nucleus contains positively charged electrons.
  • (2) The nucleus contains negatively charged protons.
  • (3) The nucleus has a positive charge and is surrounded by negatively charged electrons.
  • (4) The nucleus has a negative charge and is surrounded by positively charged electrons.
Answer: (3) The nucleus has a positive charge and is surrounded by negatively charged electrons. 

2. Which term is defined as the region in an atom where an electron is most likely to be located?

  • (1) nucleus
  • (2) orbital
  • (3) quanta
  • (4) spectra
Answer: (2) orbital 

3. What is the number of electrons in an atom of scandium?

  • (1) 21
  • (2) 24
  • (3) 45
  • (4) 66
Answer: (1) 21 

4. Which particle has the least mass?

  • (1) a proton
  • (2) an electron
  • (3) a helium atom
  • (4) a hydrogen atom
Answer: (2) an electron 

5. Which electron transition in an excited atom results in a release of energy?

  • (1) first shell to the third shell
  • (2) second shell to the fourth shell
  • (3) third shell to the fourth shell
  • (4) fourth shell to the second shell
Answer: (4) fourth shell to the second shell 

6. On the Periodic Table, the number of protons in an atom of an element is indicated by its

  • (1) atomic mass
  • (2) atomic number
  • (3) selected oxidation states
  • (4) number of valence electrons
Answer: (2) atomic numberl 

7. Which type of formula shows an element symbol for each atom and a line for each bond between atoms?

  • (1) ionic
  • (2) structural
  • (3) empirical
  • (4) molecular
Answer: (2) structural 

8. What is conserved during all chemical reactions?

  • (1) charge
  • (2) density
  • (3) vapor pressure
  • (4) melting point
Answer: (1) charge 

9. In which type of reaction can two compounds exchange ions to form two different compounds?

  • (1) synthesis
  • (2) decomposition
  • (3) single replacement
  • (4) double replacement
Answer: (4) double replacement 

10. At STP, two 5.0-gram solid samples of different ionic compounds have the same density. These solid samples could be differentiated by their

  • (1) mass
  • (2) volume
  • (3) temperature
  • (4) solubility in water
Answer: (4) solubility in water 

11. What is the number of electrons shared between the atoms in an I2 molecule?

  • (1) 7
  • (2) 2
  • (3) 8
  • (4) 4
Answer: (2) 2 

12. Which substance has nonpolar covalent bonds?

  • (1) Cl2
  • (2) SO3
  • (3) SiO2
  • (4) CCl4
Answer: (1) Cl2 

13. Compared to a potassium atom, a potassium ion has

  • (1) a smaller radius
  • (2) a larger radius
  • (3) fewer protons
  • (4) more protons
Answer: (1) a smaller radius 

14. Which form of energy is associated with the random motion of particles in a gas?

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

15. The average kinetic energy of water molecules decreases when

  • (1) H2O(ℓ) at 337 K changes to H2O(ℓ) at 300. K
  • (2) H2O(ℓ) at 373 K changes to H2O(g) at 373 K
  • (3) H2O(s) at 200. K changes to H2O(s) at 237 K
  • (4) H2O(s) at 273 K changes to H2O(ℓ) at 273 K
Answer: (1) H2O(ℓ) at 337 K changes to H2O(ℓ) at 300. K 

16. The joule is a unit of

  • (1) concentration
  • (2) energy
  • (3) pressure
  • (4) volume
Answer: (2) energy 

17. Compared to a sample of helium at STP, the same sample of helium at a higher temperature and a lower pressure

  • (1) condenses to a liquid
  • (2) is more soluble in water
  • (3) forms diatomic molecules
  • (4) behaves more like an ideal gas
Answer: (4) behaves more like an ideal gas 

18. A sample of a gas is in a sealed, rigid container that maintains a constant volume. Which changes occur between the gas particles when the sample is heated?

  • (1) The frequency of collisions increases, and the force of collisions decreases.
  • (2) The frequency of collisions increases, and the force of collisions increases.
  • (3) The frequency of collisions decreases, and the force of collisions decreases.
  • (4) The frequency of collisions decreases, and the force of collisions increases.
Answer: (2) The frequency of collisions increases, and the force of collisions increases. 

19. At STP, which gaseous sample has the same number of molecules as 3.0 liters of N2(g)?

  • (1) 6.0 L of F2(g)
  • (2) 4.5 L of N2(g)
  • (3) 3.0 L of H2(g)
  • (4) 1.5 L of Cl2(g)
Answer: (3) 3.0 L of H2(g) 

20. Distillation of crude oil from various parts of the world yields different percentages of hydrocarbons. Which statement explains these different percentages?

  • (1) Each component in a mixture has a different solubility in water.
  • (2) Hydrocarbons are organic compounds.
  • (3) The carbons in hydrocarbons may be bonded in chains or rings.
  • (4) The proportions of components in a mixture can vary.
Answer: (4) The proportions of components in a mixture can vary. 

21. In which 1.0-gram sample are the particles arranged in a crystal structure?

  • (1) CaCl2(s)
  • (2) C2H6(g)
  • (3) CH3OH(ℓ)
  • (4) CaI2(aq)
Answer: (1) CaCl2(s) 

22. When a reversible reaction is at equilibrium, the concentration of products and the concentration of reactants must be

  • (1) decreasing
  • (2) increasing
  • (3) constant
  • (4) equal
Answer: (3) constant 

23. In chemical reactions, the difference between the potential energy of the products and the potential energy of the reactants is equal to the

  • (1) activation energy
  • (2) ionization energy
  • (3) heat of reaction
  • (4) heat of vaporization
Answer: (3) heat of reaction 

24. What occurs when a catalyst is added to a chemical reaction?

  • (1) an alternate reaction pathway with a lower activation energy
  • (2) an alternate reaction pathway with a higher activation energy
  • (3) the same reaction pathway with a lower activation energy
  • (4) the same reaction pathway with a higher activation energy
Answer: (1) an alternate reaction pathway with a lower activation energy 

25. What is the name of the compound with the formula CH3CH2CH2NH2?

  • (1) 1-propanol
  • (2) 1-propanamine
  • (3) propanal
  • (4) propanamide
Answer: (2) 1-propanamine 

26. Which compound is an isomer of C2H5OC2H5?

  • (1) CH3COOH
  • (2) C2H5COOCH3
  • (3) C3H7COCH3
  • (4) C4H9OH
Answer: (4) C4H9OH 

27. Ethanoic acid and 1-butanol can react to produce water and a compound classified as an

  • (1) aldehyde
  • (2) amide
  • (3) ester
  • (4) ether
Answer: (3) ester 

28. During an oxidation-reduction reaction, the number of electrons gained is

  • (1) equal to the number of electrons lost
  • (2) equal to the number of protons gained
  • (3) less than the number of electrons lost
  • (4) less than the number of protons gained
Answer: (1) equal to the number of electrons lost 

29. Which process requires energy for a nonspontaneous redox reaction to occur?

  • (1) deposition
  • (2) electrolysis
  • (3) alpha decay
  • (4) chromatography
Answer: (2) electrolysis 

30. Which pair of compounds represents one Arrhenius acid and one Arrhenius base?

  • (1) CH3OH and NaOH
  • (2) CH3OH and HCl
  • (3) HNO3 and NaOH
  • (4) HNO3 and HCl
Answer: (3) HNO3 and NaOH 

 

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