August 2005 Chemistry Regents #1-10
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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50 |
Questions | Answer | Explanations |
| 1 Which subatomic particle has a negative charge? (1) proton (3) neutron (2) electron (4) positron | 2 | electrons = neg proton = + neutron= no charge |
| 2 Which statement best describes the nucleus of an aluminum atom? (1) It has a charge of +13 and is surrounded by a total of 10 electrons. (2) It has a charge of +13 and is surrounded by a total of 13 electrons. (3) It has a charge of –13 and is surrounded by a total of 10 electrons. (4) It has a charge of –13 and is surrounded by a total of 13 electrons. | 2 | nucleus protons only charge= 13 atom proton =electrons |
| 3 The atomic mass of an element is the weighted average of the (1) number of protons in the isotopes of that element (2) number of neutrons in the isotopes of that element (3) atomic numbers of the naturally occurring isotopes of that element (4) atomic masses of the naturally occurring isotopes of that element | 4 | definition |
| 4 In which pair do the particles have approximately the same mass? (1) proton and electron (2) proton and neutron (3) neutron and electron (4) neutron and beta particle | 2 | proton, neutrons =1 amu each electrons =1/1836 amu |
| 5 Two different samples decompose when heated. Only one of the samples is soluble in water. Based on this information, these two samples are (1) both the same element (2) two different elements (3) both the same compound (4) two different compounds | 4 | decompose= compounds |
| 6 The elements located in the lower left corner of the Periodic Table are classified as (1) metals (3) metalloids (2) nonmetals (4) noble gases | 1 | metals= bottom left nonmetals = top right |
| 7 Which of these elements has the lowest melting point? (1) Li (3) K (2) Na (4) Rb | 4 | see table S |
| 8 Which list consists of elements that have the most similar chemical properties? (1) Mg, Al, and Si (3) K, Al, and Ni (2) Mg, Ca, and Ba (4) K, Ca, and Ga | 2 | same group |
| 9 The correct chemical formula for iron(II) sulfide is (1) FeS (3) FeSO4 (2) Fe2S3 (4) Fe2(SO4)3 | 1 | Fe2+ S2- 1:1 ratio |
| 10 Which list consists of types of chemical formulas? (1) atoms, ions, molecules (2) metals, nonmetals, metalloids (3) empirical, molecular, structural (4) synthesis, decomposition, neutralization | 3 | see answer |