Earth Science June 2003

Earth Science June 2003 Questions Answers Keys.

The University of the State of New York
REGENTS HIGH SCHOOL EXAMINATION
PHYSICAL SETTING
CHEMISTRY
Tuesday, June 24, 2003 — 9:15 a.m. to 12:15 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. The atomic number of an atom is always equal to the number of its

(1) protons, only
(2) neutrons, only
(3) protons plus neutrons
(4) protons plus electrons

Answer: (1) protons, only

2. Which subatomic particle has no charge?

(1) alpha particle
(2) beta particle
(3) neutron
(4) electron

Answer: (3) neutron

3. When the electrons of an excited atom return to a lower energy state, the energy emitted can result in the production of

(1) alpha particles
(2) isotopes
(3) protons
(4) spectra

Answer: (4) spectra

4. The atomic mass of an element is calculated using the

(1) atomic number and the ratios of its naturally occurring isotopes
(2) atomic number and the half-lives of each of its isotopes
(3) masses and the ratios of its naturally occurring isotopes
(4) masses and the half-lives of each of its isotopes

Answer: (3) masses and the ratios of its naturally occurring isotopes

5. The region that is the most probable location of an electron in an atom is

(1) the nucleus
(2) an orbital
(3) the excited state
(4) an ion

Answer: (2) an orbital

6. Which is a property of most nonmetallic solids?

(1) high thermal conductivity
(2) high electrical conductivity
(3) brittleness
(4) malleability

Answer: (3) brittleness

7. Alpha particles are emitted during the radioactive decay of

(1) carbon-14
(2) neon-19
(3) calcium-37
(4) radon-222

Answer: (4) radon-222

8. Which is an empirical formula?

(1) P₂O₅
(2) P₄O₆
(3) C₂H₄
(4) C₃H₆

Answer: (1) P₂O₅

9. Which substance can be decomposed by a chemical change?

(1) Co
(2) CO
(3) Cr
(4) Cu

Answer: (2) CO

10. The percent by mass of calcium in the compound calcium sulfate (CaSO₄) is approximately

(1) 15%
(2) 29%
(3) 34%
(4) 47%

Answer: (2) 29%

11. What is represented by the dots in a Lewis electron-dot diagram of an atom of an element in Period 2 of the Periodic Table?

(1) the number of neutrons in the atom
(2) the number of protons in the atom
(3) the number of valence electrons in the atom
(4) the total number of electrons in the atom

Answer: (3) the number of valence electrons in the atom

12. Which type of chemical bond is formed between two atoms of bromine?

(1) metallic
(2) hydrogen
(3) ionic
(4) covalent

Answer: (4) covalent

13. Which of these formulas contains the most polar bond?

(1) H–Br
(2) H–Cl
(3) H–F
(4) H–I

Answer: (3) H–F

14. According to Table F, which of these salts is least soluble in water?

(1) LiCl
(2) RbCl
(3) FeCl₂
(4) PbCl₂

Answer: (4) PbCl₂

15. Which of these terms refers to matter that could be heterogeneous?

(1) element
(2) mixture
(3) compound
(4) solution

Answer: (2) mixture

16. In which material are the particles arranged in a regular geometric pattern?

(1) CO₂(g)
(2) NaCl(aq)
(3) H₂O()
(4) C₁₂H₂₂O₁₁(s)

Answer: (4) C₁₂H₂₂O₁₁(s)

17. Which change is exothermic?

(1) freezing of water
(2) melting of iron
(3) vaporization of ethanol
(4) sublimation of iodine

Answer: (1) freezing of water

18. Which type of change must occur to form a compound?

(1) chemical
(2) physical
(3) nuclear
(4) phase

Answer: (1) chemical

19. Which formula correctly represents the composition of iron (III) oxide?

(1) FeO₃
(2) Fe₂O₃
(3) Fe₃O
(4) Fe₃O₂

Answer: (2) Fe₂O₃

20. Given the reaction:

PbCl₂(aq) + Na₂CrO₄(aq) → PbCrO₄(s) + 2 NaCl(aq)

What is the total number of moles of NaCl formed when 2 moles of Na₂CrO₄ react completely?

(1) 1 mole
(2) 2 moles
(3) 3 moles
(4) 4 moles

Answer: (4) 4 moles

21. Which hydrocarbon is saturated?

(1) propene
(2) ethyne
(3) butene
(4) heptane

Answer: (4) heptane

22. Which statement correctly describes an endothermic chemical reaction?

(1) The products have higher potential energy than the reactants, and the ∆H is negative.
(2) The products have higher potential energy than the reactants, and the ∆H is positive.
(3) The products have lower potential energy than the reactants, and the ∆H is negative.
(4) The products have lower potential energy than the reactants, and the ∆H is positive.

Answer: (2) The products have higher potential energy than the reactants, and the ∆H is positive.

23. At standard pressure when NaCl is added to water, the solution will have a

(1) higher freezing point and a lower boiling point than water
(2) higher freezing point and a higher boiling point than water
(3) lower freezing point and a higher boiling point than water
(4) lower freezing point and a lower boiling point than water

Answer: (3) lower freezing point and a higher boiling point than water

24. Which element has atoms that can form single, double, and triple covalent bonds with other atoms of the same element?

(1) hydrogen
(2) oxygen
(3) fluorine
(4) carbon

Answer: (4) carbon

25. Which compound is an isomer of pentane?

(1) butane
(2) propane
(3) methyl butane
(4) methyl propane

Answer: (3) methyl butane

26. In which substance does chlorine have an oxidation number of +1?

(1) Cl₂
(2) HCl
(3) HClO
(4) HClO₂

Answer: (3) HClO

27. Which statement is true for any electrochemical cell?

(1) Oxidation occurs at the anode, only.
(2) Reduction occurs at the anode, only.
(3) Oxidation occurs at both the anode and the cathode.
(4) Reduction occurs at both the anode and the cathode.

Answer: (1) Oxidation occurs at the anode, only.

28. Given the equation:

2 Al + 3 Cu²⁺ → 2 Al³⁺ + 3 Cu

The reduction half-reaction is

(1) Al → Al³⁺ + 3e^–
(2) Cu²⁺ + 2e^– → Cu
(3) Al + 3e^– → Al³⁺
(4) Cu²⁺ → Cu + 2e^–

Answer: (2) Cu²⁺ + 2e^– → Cu

29. Which 0.1 M solution contains an electrolyte?

(1) C₆H₁₂O₆(aq)
(2) CH₃COOH(aq)
(3) CH₃OH(aq)
(4) CH₃OCH₃(aq)

Answer: (2) CH₃COOH(aq)

30. Which equation represents a neutralization reaction?

(1) Na₂CO₃ + CaCl₂ → 2 NaCl + CaCO₃
(2) Ni(NO₃)₂ + H₂S → NiS + 2 HNO₃
(3) NaCl + AgNO₃ → AgCl + NaNO₃
(4) H₂SO₄ + Mg(OH)₂ → MgSO₄ + 2 H₂O

Answer: (4) H₂SO₄ + Mg(OH)₂ → MgSO₄ + 2 H₂O

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