January 2016 Chemistry Regents #31-35
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Questions | Answer | Links | Explanations |
| 31 Which electron configuration represents an atom of chlorine in an excited state? (1) 2–7-7 (3) 2-8-7 (2) 2-7-8 (4) 2-8-8 | 2 | ground state 2-8-7 (17 ELECTRONS) excited state moves an electron to a higher energy level 2-7-8 still has 17 electrons | |
| 32 Given the balanced equation representing a reaction occurring at 101.3 kilopascals and 298 K. 2H2(g) + O2(g) → 2H2O(l) + energy What is the net amount of energy released when one mole of H2O(l) is produced? (1) 241.8 k] (3) 4836kJ (2) 285.8 k] (4) 571.6 k] | 2 | the reaction is for 2 moles of water so cut the amount in half | |
| 33 Element X reacts with copper to form the compounds CuX and CuX2. In which group on the Periodic Table is element X found? (1) Group 1 (3) Group 13 (2) Group 2 (4) Group 17 | 4 | X must be -1 so group 17 since Cu can only be +1 or +2 | |
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| 34 What is the mass of 1.5 moles of CO2? (1) 66 g (3) 33 g (2) 44 g (4) 29 g | 1 | 1.5 moles x 44 grams /mole | |
| 35 Given the balanced equation representing a reaction: K2CO3(aq) + BaCl2(aq) → 2KCl(aq) + BaCO3(s) Which type of reaction is represented by this equation? (1) synthesis (2) decomposition (3) single replacement (4) double replacement | 4 | double replacement double switches ions | |
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