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level: 1/11/2021

Questions and Answers List

level questions: 1/11/2021

Question	Answer
We generally report a measurement by recording all of the certain digits plus ____ uncertain digit(s). A) no B) one C) two D) three E) four	ANS: B DIF: Easy REF: 1.5 KEY: Chemistry \| general chemistry \| general concepts \| measurement \| significant figures MSC: Conceptual
Body temperature is about 309 K. On a cold day, what volume of air at 276 K must a person with a lung capacity of 2.2 L breathe in to fill the lungs? A) 2.46 L B) 1.97 L C) 2.08 L D) 3.93 L E) none of these	ANS: B PTS: 1 DIF: Easy REF: 5.2 KEY: Chemistry \| general chemistry \| phases \| gas \| empirical gas laws \| Charles's law MSC: Quantitative
A general reaction written as A + 2B  C + 2D is studied and yields the following data: [A]0 [B]0 Initial [C]/t 0.150 M 0.150 M 8.00 * 10^–3 mol/L·s 0.150 M 0.300 M 1.60 * 10^–2 mol/L·s 0.300 M 0.150 M 3.20 * 10^–2 mol/L·s 13. What is the order of the reaction with respect to B? A) 0 B) 1 C) 2 D) 3 E) 4	ANS: B PTS: 1 DIF: Easy REF: 12.3 KEY: Chemistry \| general chemistry \| rates of reaction \| reaction rate \| dependence of rate on concentration \| reaction order
You have solutions of 0.200 M HNO2 and 0.200 M KNO2 (Ka for HNO2 = 4.00 * 10^–4). A buffer of pH 3.000 is needed. What volumes of HNO2 and KNO2 are required to make 1 liter of buffered solution? A) 500 mL of each B) 286 mL HNO2; 714 mL KNO2 C) 413 mL HNO2; 587 mL KNO2 D) 714 mL HNO2; 286 mL KNO2 E) 587 mL HNO2; 413 mL KNO2	ANS: D PTS: 1 DIF: Difficult REF: 15.2 KEY: Chemistry \| general chemistry \| acids and bases \| solutions of a weak acid or base with another solute \| buffer \| Henderson-Hasselbalch equation
How many electrons are transferred in the following reaction? 2ClO3– + 12H+ + 10I–  5I2 + Cl2 + 6H2O A) 12 B) 5 C) 2 D) 30 E) 10	ANS: E PTS: 1 DIF: Easy REF: 18.1 KEY: Chemistry \| general chemistry \| electrochemistry \| half-reaction \| balancing chemical equation