June 2016 Chemistry Regents #11-15
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Questions | Answer | Links | Explanations |
11 A 10.0-gram sample of nitrogen is at STP. Which property increase when the sample is cooled to 72 K at standard pressure? (1) mass (3) density (2) volume (4) temperature | 3 | nitrogen is a gas down to 77K then it turns to a liquid 72K N2 is a liquid which has a larger density than N2 gas | |
12 Which element is a gas at STP? (1) sulfur (3) potassium (2) xenon (4) phosphorus | 2 | the noble gas....Xe | |
13 A 5.0-gram sample of Fe(s) is to be placed in 100. milliliters of HCl(aq). Which changes will result in the fastest rate of reaction? (1) increasing the surface area of Fe(s) and increasing the concentration of HCl(aq) (2) increasing the surface area of Fe(s) and decreasing the concentration of HCl(aq) (3) decreasing the surface area of Fe(s) and increasing the concentration of HCl(aq) (4) decreasing the surface area of Fe(s) and decreasing the concentration of HCl(aq) | 1 | larger surface area and larger concentration makes reaction rates faster | |
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14 Which process is commonly used to separate a mixture of ethanol and water? (1) distillation (3) filtration (2) ionization (4) titration | 1 | since they are both liquids and have different boiling points use distillation | |
15 A sample of hydrogen gas will behave most like an ideal gas under the conditions of (1) low pressure and low temperature (2) low pressure and high temperature (3) high pressure and low temperature (4) high pressure and high temperature | 2 | ideal vacation questions high temperature and low pressure | |
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