June 2013 Chemistry Regents #4150
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Questions 
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Explanations 
41 Given the equation representing a system at equilibrium:
When the concentration of Cl^{}_{(aq)} is increased, the concentration of Ag^{+}_{(aq)} (1) decreases, and the amount of AgCl(s) increases (2) decreases, and the amount of AgCl(s) decreases (3) increases, and the amount of AgCl(s) increases (4) increases, and the amount of AgCl(s) decreases 
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42 Which particle diagram represents a sample of matter that can not be broken down by chemical means? 
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43 Which formula represents an unsaturated hydrocarbon? 
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44 When the pH of a solution is changed from 4 to 3, the hydronium ion concentration of the solution (1) decreases by a factor of 10 (2) increases by a factor of 10 (3) decreases by a factor of 100 (4) increases by a factor of 100 
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45 Three samples of the same solution are tested, each with a different indicator. All three indicators, bromthymol blue, bromcresol green, and thymol blue, appear blue if the pH of the solution is (1) 4.7 (2) 6.0 (3) 7.8 (4) 9.9 
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46 A 10.0milliliter sample of NaOH(aq) is neutralized by 40.0 milliliters of 0.50 M HCl. What is the molarity of the NaOH(aq)? (1) 1.0 M (3) 0.25 M (2) 2.0 M (4) 0.50 M 
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47 Radiation is spontaneously emitted from hydrogen3 nuclei, but radiation is not spontaneously emitted from hydrogenl nuclei or hydrogen2 nuclei. Which hydrogen nuclei are stable? (1) nuclei of Hl and H2, only (2) nuclei of Hl and H3, only (3) nuclei of H2 and H3, only (4) nuclei of Hl, H2, and H3 
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48 Given the equation representing a nuclear reaction in which X represents a nuclide: 
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49 After decaying for 48 hours, l/16 of the original mass of a radioisotope sample remains unchanged. What is the halflife of this radioisotope? (1) 3.0 h (3) 12 h (2) 9.6 h (4) 24 h 
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50 Which balanced equation represents nuclear fusion? 
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