June 2014 Chemistry Regents #46-50
Highlight to reveal answers and explanations
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Questions | Answer | Links | Explanations |
46 What is the oxidation number of manganese in KMnO4? (1) +7 (3) +3 (2) +2 (4) +4 | 1 | link | K is +1 O is -2 x 4 so -8 Leaving Mn to be +7 so it all adds to 0 |
47 When the pH of an aqueous solution is changed from 1 to 2, the concentration of hydronium ions in the solution is (1) decreased by a factor of 2 (2) decreased by a factor of 10 (3) increased by a factor of 2 (4) increased by a factor or 10 | 2 | link | each pH unit change is a 10 fold change in hydronium hydronium increases if the pH decreases (more acidic) and decreases as the pH increase (more basic)
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48 What is the color of the indicator thymol blue in a solution that has a pH of 11? (1) red (3) pink (2) blue (4) yellow | 2 | link | table M thymol blue above 9.6 is blue |
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49 Which formulas represent compounds that are isomers of each other? | 3 | link | isomer=same formula different structure count the atoms, but is must be a different structure |
50 One beneficial use of radioisotopes is (1) detection of disease (2) neutralization of an acid spill (3) decreasing the dissolved O2(g) level in seawater (4) increasing the concentration of CO2(g) in the atmosphere | 1 | link | one of the many uses for radioactive elements |
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