1. 1 According to the wave-mechanical model of the atom, an orbital is a region of the most probable location of (1) an alpha particle (3) an electron (2) a gamma ray (4) a proton   1   2   3   4   Hint Half-n-half Clue   2. 2 Which particles have approximately the same mass? (1) an electron and an alpha particle (2) an electron and a proton (3) a neutron and an alpha particle (4) a neutron and a proton   1   2   3   4   Half-n-half Clue   3. 3 During a flame test, a lithium salt produces a characteristic red flame. This red color is produced when electrons in excited lithium atoms (1) are lost by the atoms (2) are gained by the atoms (3) return to lower energy states within the atoms (4) move to higher energy states within the atoms   1   2   3   4   Half-n-half Clue   4. 4 Compared to the energy and charge of the electrons in the first shell of a Be atom, the electrons in the second shell of this atom have (1) less energy and the same charge (2) less energy and a different charge (3) more energy and the same charge (4) more energy and a different charge   1   2   3   4   Half-n-half Clue   5. 5 Which quantity can vary among atoms of the same element? (1) mass number (2) atomic number (3) number of protons (4) number of electrons   1   2   3   4   Half-n-half Clue   6. 6 Which substances have atoms of the same element but different molecular structures? (1) He(g) and Ne(g) (3) K(s) and Na(s) (2) O2(g) and O3(g) (4) P4(s) and S8(s)   1   2   3   4   Half-n-half Clue   7. 7 An atom that has 13 protons and 15 neutrons is an isotope of the element (1) nickel (3) aluminum (2) silicon (4) phosphorus   1   2   3   4   Half-n-half Clue   8. 8 Which elements have the most similar chemical properties? (1) Si, As, and Te (3) Mg, Sr, and Ba (2) N2, O2, and F2 (4) Ca, Cs, and Cu   1   2   3   4   Half-n-half Clue   9. 9 Which list includes three types of chemical formulas for organic compounds? (1) covalent, metallic, isotopic (2) covalent, metallic, molecular (3) empirical, structural, isotopic (4) empirical, structural, molecular   1   2   3   4   Half-n-half Clue   10. 10 In a bond between an atom of carbon and an atom of fluorine, the fluorine atom has a (1) weaker attraction for electrons (2) stronger attraction for electrons (3) smaller number of first-shell electrons (4) larger number of first-shell electrons   1   2   3   4   Half-n-half Clue   11. 11 A sample of CO2(s) and a sample of CO2(g) differ in their (1) chemical compositions (2) empirical formulas (3) molecular structures (4) physical properties   1   2   3   4   Half-n-half Clue   12. 12 Which statement defines the temperature of a sample of matter? (1) Temperature is a measure of the total electromagnetic energy of the particles. (2) Temperature is a measure of the total thermal energy of the particles. (3) Temperature is a measure of the average potential energy of the particles. (4) Temperature is a measure of the average kinetic energy of the particles.   1   2   3   4   Half-n-half Clue   13. 13 For a chemical reaction, the difference between the potential energy of the products and the potential energy of the reactants is equal to the (1) heat of fusion (2) heat of reaction (3) activation energy of the forward reaction (4) activation energy of the reverse reaction   1   2   3   4   Half-n-half Clue   14. 14 Which equation represents sublimation? (1) Hg(ℓ) → Hg(s) (3) NH3(g) → NH3(ℓ) (2) H2O(s) → H2O(g) (4) CH4(ℓ) → CH4(g)   1   2   3   4   Half-n-half Clue   15. 15 Which statement describes the particles of an ideal gas, based on the kinetic molecular theory? (1) The motion of the gas particles is orderly and circular. (2) The gas particles have no attractive forces between them. (3) The gas particles are larger than the dis- tances separating them. (4) As the gas particles collide, the total energy of the system decreases.   1   2   3   4   Half-n-half Clue   16. 16 Two grams of potassium chloride are completely dissolved in a sample of water in a beaker. This solution is classified as (1) an element (2) a compound (3) a homogeneous mixture (4) a heterogeneous mixture   1   2   3   4   Half-n-half Clue   17. 17 Which compound has the strongest hydrogen bonding between its molecules? (1) HBr (3) HF (2) HCl (4) HI   1   2   3   4   Half-n-half Clue   18. 18 Powdered sulfur is yellow, and powdered iron is gray. When powdered sulfur and powdered iron are mixed at 20°C, the powdered iron (1) becomes yellow (3) remains ionic (2) becomes a liquid (4) remains magnetic   1   2   3   4   Half-n-half Clue   19. 19 An effective collision between reactant particles requires the particles to have the proper (1) charge and mass (2) charge and orientation (3) energy and mass (4) energy and orientation   1   2   3   4   Half-n-half Clue   20. 20 Which term is defined as a measure of the disorder of a system? (1) heat (3) kinetic energy (2) entropy (4) activation energy   1   2   3   4   Half-n-half Clue   21. 21 Which process is used to determine the concen- tration of an acid? (1) chromatography (3) electrolysis (2) distillation (4) titration   1   2   3   4   Half-n-half Clue   22. 22 The compounds CH3OCH3 and CH3CH2OH have different functional groups. Therefore, these compounds have different (1) chemical properties (2) gram-formula masses (3) percent compositions by mass (4) numbers of atoms per molecule   1   2   3   4   Half-n-half Clue   23. 23 Which term identifies the half-reaction that occurs at the anode of an operating electro- chemical cell? (1) oxidation (3) neutralization (2) reduction (4) transmutation   1   2   3   4   Half-n-half Clue   24. 24 During the operation of a voltaic cell, the cell produces (1) electrical energy spontaneously (2) chemical energy spontaneously (3) electrical energy nonspontaneously (4) chemical energy nonspontaneously   1   2   3   4   Half-n-half Clue   25. 25 In which type of chemical reaction are electrons transferred? (1) organic addition (2) oxidation-reduction (3) double replacement (4) acid-base neutralization   1   2   3   4   Half-n-half Clue   26. 26 A substance that dissolves in water and produces hydronium ions as the only positive ions in the solution is classified as (1) an alcohol (3) a base (2) an acid (4) a salt   1   2   3   4   Half-n-half Clue   27. 27 According to one acid-base theory, a base is an (1) H+ acceptor (3) Na+ acceptor (2) H+ donor (4) Na+ donor   1   2   3   4   Half-n-half Clue   28. 28 Which compound is an electrolyte? (1) CCl4 (3) C6H12O6 (2) CH3OH (4) Ca(OH)2   1   2   3   4   Half-n-half Clue   29. 29 Which term identifies a type of nuclear reaction? (1) fermentation (3) reduction (2) deposition (4) fission   1   2   3   4   Half-n-half Clue   30. 30 Which radioisotopes have the same decay mode and have half-lives greater than 1 hour? (1) Au-198 and N-16 (3) I-131 and P-32 (2) Ca-37 and Fe-53 (4) Tc-99 and U-233   1   2   3   4   Half-n-half Clue