Midterm-3 - MULTIPLE CHOICE. (1 pt. each) Choose the one...

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MULTIPLE CHOICE. (1 pt. each) Choose the one alternative that best completes the statement or answers the question. 1) What will the pH be if 0.10 moles of sodium formate (NaHCOO) is added to 1.0 L of a solution of 0.10 M formic acid (HCOOH)? (K a for formic acid = 1.8 x 10 - 4) 1) A) 3.74 B) 4.24 C) 4.74 D) 5.34 E) 8.33 2) The dilution of a buffer solution with a small amount of water will: 2) A) lower the pH. B) raise the pH. C) not change the pH significantly. D) change the [A - ]/[HA] ratio 3) What is the most effective pH buffering range for a benzoic acid/benzoate buffer? (benzoic acid K a = 6.3 × 10 - 5) 3) A) 8.8 - 10.8 B) 5.3 - 7.3 C) 4.7 - 6.7 D) 3.2 - 5.2 E) none of the above 4) How many grams of (NH 4 ) 2 SO 4 (132.14 g/mol) should be added to 425 mL of a 0.258 M solution of NH 3 to acheive a buffer solution with a pH of 9.44? (K b for NH 3 = 1.8 x 10 - 5) 4) A) 4.8 g B) 1.6 x 10 - 4 g C) 0.029 g D) 18 g E) 114 g 5) A 20.00 mL sample of H 3 PO 4 is titrated to a phenolphthalein end point with 18.67 mL of 0.1885 M NaOH. If the phenolphthalein color change occurs at the second eqivalence point, what is the molarity of the acid. 5) A) 3.520 M B) 1.088 M C) 0.3520 M D) 0.1760 M E) 0.08798 M 6) A 0.542 g sample of an unknown monoprotic weak acid requires 28.67 mL of 0.1093 M NaOH for neutralization. What is the molar mass of the acid? 6) A) 88.0 g/mol B) 109 g/mol C) 173 g/mol D) 218 g/mol E) 352 g/mol 1
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7) The following titration curve is for 25.00 mL of 0.100 M H 3 PO 4 , titrated with 0.100 M NaOH. What volume of NaOH solution was added to get to point C?
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Midterm-3 - MULTIPLE CHOICE. (1 pt. each) Choose the one...

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