Earth Science August 2004

Earth Science August 2004 Questions Answers Keys.

The University of the State of New York
REGENTS HIGH SCHOOL EXAMINATION
PHYSICAL SETTING
CHEMISTRY
Tuesday, August 17, 2004 — 12:30 to 3:30 p.m., only

Directions : For each statement or question, write on the 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 Reference Tables for Physical Setting/Chemistry.

1. Which of these phrases best describes an atom?

  • (1) a positive nucleus surrounded by a hard negative shell
  • (2) a positive nucleus surrounded by a cloud of negative charges
  • (3) a hard sphere with positive particles uniformly embedded
  • (4) a hard sphere with negative particles uniformly embedded
Answer: (2) a positive nucleus surrounded by a cloud of negative charges 

2. Which statement is true about a proton and an electron?

  • (1) They have the same masses and the same charges.
  • (2) They have the same masses and different charges.
  • (3) They have different masses and the same charges.
  • (4) They have different masses and different charges.
Answer: (4) They have different masses and different charges. 

3. The atomic mass of an element is the weighted average of the masses of

  • (1) its two most abundant isotopes
  • (2) its two least abundant isotopes
  • (3) all of its naturally occurring isotopes
  • (4) all of its radioactive isotopes
Answer: (3) all of its naturally occurring isotopes 

4. What determines the order of placement of the elements on the modern Periodic Table?

  • (1) atomic number
  • (2) atomic mass
  • (3) the number of neutrons, only
  • (4) the number of neutrons and protons
Answer: (1) atomic number 

5. Which compound contains only covalent bonds?

  • (1) NaOH
  • (2) Ba(OH)2
  • (3) Ca(OH)2
  • (4) CH3OH
Answer: (4) CH3OH

 

6. At 298 K, oxygen (O2) and ozone (O3) have different properties because their

  • (1) atoms have different atomic numbers
  • (2) atoms have different atomic masses
  • (3) molecules have different molecular structures
  • (4) molecules have different average kinetic energies
Answer: (3) molecules have different molecular structures 

7. Which substance represents a compound?

  • (1) C(s)
  • (2) Co(s)
  • (3) CO(g)
  • (4) O2(g)
Answer: (3) CO(g) 

8. All chemical reactions have a conservation of

  • (1) mass, only
  • (2) mass and charge, only
  • (3) charge and energy, only
  • (4) mass, charge, and energy
Answer: (4) mass, charge, and energy 

9. Which characteristic is a property of molecular substances?

  • (1) good heat conductivity
  • (2) good electrical conductivity
  • (3) low melting point
  • (4) high melting point
Answer: (3) low melting point 

10. Given the Lewis electron-dot diagram:

Which electrons are represented by all of the dots?

  • (1) the carbon valence electrons, only
  • (2) the hydrogen valence electrons, only
  • (3) the carbon and hydrogen valence electrons
  • (4) all of the carbon and hydrogen electrons
Answer: (3) the carbon and hydrogen valence electrons 

11. Which grouping of the three phases of bromine is listed in order from left to right for increasing distance between bromine molecules?

  • (1) gas, liquid, solid
  • (2) liquid, solid, gas
  • (3) solid, gas, liquid
  • (4) solid, liquid, gas
Answer: (4) solid, liquid, gas 

12. Which statement concerning elements is true?

  • (1) Different elements must have different numbers of isotopes.
  • (2) Different elements must have different numbers of neutrons.
  • (3) All atoms of a given element must have the same mass number.
  • (4) All atoms of a given element must have the same atomic number.
Answer: (4) All atoms of a given element must have the same atomic number. 

13. At room temperature, the solubility of which solute in water would be most affected by a change in pressure?

  • (1) methanol
  • (2) sugar
  • (3) carbon dioxide
  • (4) sodium nitrate
Answer: (3) carbon dioxide 

14. Based on Reference Table I, which change occurs when pellets of solid NaOH are added to water and stirred?

  • (1) The water temperature increases as chemical energy is converted to heat energy.
  • (2) The water temperature increases as heat energy is stored as chemical energy.
  • (3) The water temperature decreases as chemical energy is converted to heat energy.
  • (4) The water temperature decreases as heat energy is stored as chemical energy.
Answer: (1) The water temperature increases as chemical energy is converted to heat energy. 

15. The concept of an ideal gas is used to explain

  • (1) the mass of a gas sample
  • (2) the behavior of a gas sample
  • (3) why some gases are monatomic
  • (4) why some gases are diatomic
Answer: (2) the behavior of a gas sample 

16. Molecules in a sample of NH3() are held closely together by intermolecular forces

  • (1) existing between ions
  • (2) existing between electrons
  • (3) caused by different numbers of neutrons
  • (4) caused by unequal charge distribution
Answer: (4) caused by unequal charge distribution 

17. Which process represents a chemical change?

  • (1) melting of ice
  • (2) corrosion of copper
  • (3) evaporation of water
  • (4) crystallization of sugar
Answer: (2) corrosion of copper 

18. At STP, which 4.0-gram zinc sample will react fastest with dilute hydrochloric acid?

  • (1) lump
  • (2) bar
  • (3) powdered
  • (4) sheet metal
Answer: (3) powdered 

19. Which information about a chemical reaction is provided by a potential energy diagram?

  • (1) the oxidation states of the reactants and products
  • (2) the average kinetic energy of the reactants and products
  • (3) the change in solubility of the reacting substances
  • (4) the energy released or absorbed during the reaction
Answer: (4) the energy released or absorbed during the reaction 

20. A catalyst works by

  • (1) increasing the potential energy of the reactants
  • (2) increasing the energy released during a reaction
  • (3) decreasing the potential energy of the products
  • (4) decreasing the activation energy required for a reaction
Answer: (4) decreasing the activation energy required for a reaction 

21. Even though the process is endothermic, snow can sublime. Which tendency in nature accounts for this phase change?

  • (1) a tendency toward greater entropy
  • (2) a tendency toward greater energy
  • (3) a tendency toward less entropy
  • (4) a tendency toward less energy
Answer: (1) a tendency toward greater entropy 

22. What is the IUPAC name of the compound with the structural formula shown below?

  • (1) 2-pentene
  • (2) 3-pentene
  • (3) 2-pentyne
  • (4) 3-pentyne
Answer: (1) 2-pentene 

23. Molecules of 1-bromopropane and 2-bromopropane differ in

  • (1) molecular formula
  • (2) structural formula
  • (3) number of carbon atoms per molecule
  • (4) number of bromine atoms per molecule
Answer: (2) structural formula 

24. Which half-reaction correctly represents reduction?

  • (1) Ag → Ag+ + e
  • (2) F2 → 2 F + 2e
  • (3) Au3+ + 3e → Au
  • (4) Fe2+ + e → Fe3+
Answer: (3) Au3+ + 3e → Au 

25. In a redox reaction, how does the total number of electrons lost by the oxidized substance compare to the total number of electrons gained by the reduced substance?

  • (1) The number lost is always greater than the number gained.
  • (2) The number lost is always equal to the number gained.
  • (3) The number lost is sometimes equal to the number gained.
  • (4) The number lost is sometimes less than the number gained.
Answer: (2) The number lost is always equal to the number gained. 

26. Which reaction is an example of an oxidationreduction reaction?

  • (1) AgNO3 + KI → AgI + KNO3
  • (2) Cu + 2 AgNO3 → Cu(NO3) 2 + 2 Ag
  • (3) 2 KOH + H2SO4 → K2SO4 + 2 H2O
  • (4) Ba(OH)2 + 2 HCl → BaCl2 + 2 H2O
Answer: (2) Cu + 2 AgNO3 → Cu(NO3) 2 + 2 Ag 

27. Which compound is an Arrhenius base?

  • (1) CH3OH
  • (2) CO2
  • (3) LiOH
  • (4) NO2
Answer: (2) CO2 

28. The only positive ion found in an aqueous solution of sulfuric acid is the

  • (1) hydroxide ion
  • (2) hydronium ion
  • (3) sulfite ion
  • (4) sulfate ion
Answer: (2) hydronium ion 

29. Which process uses a volume of solution of known concentration to determine the concentration of another solution?

  • (1) distillation
  • (2) substitution
  • (3) transmutation
  • (4) titration
Answer: (4) titration 

30. Which pH change represents a hundredfold increase in the concentration of H3O+ ?

  • (1) pH 5 to pH 7
  • (2) pH 13 to pH 14
  • (3) pH 3 to pH 1
  • (4) pH 4 to pH 3
Answer: (2) pH 13 to pH 14 

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