1995 nat - U.S. National Chemistry Olympiad 1995 National...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
U.S. National Chemistry Olympiad 1995 National Test Go to Answers 1. Which 0.1 M solution will form a precipitate with excess 0.1 M KOH but not with excess 0.1 M NH 3 ? (A) AgNO 3 (B) AlCl 3 (C) BaCl 2 (D) MgCl 2 2. The members of which pair are most similar in color? (A) chlorine, Cl 2 (g), and bromine, Br 2 (l) (B) silver chloride, AgCl(s), and silver sulfide, Ag 2 S(s) (C) copper(II) chloride, CuCl 2 (s), and calcium chloride, CaCl 2 (s) (D) potassium permanganate, KMnO 4 (aq), and iodine, I 2 (g) 3. Which compound is expected to be the least soluble in water? (A) CH 3 COOH (B) CH 3 COONa (C) CH 3 OCH 3 (D) CH 3 CH 2 OH 4. When a small amount of solid calcium phosphide, Ca 3 P 2 , is added to water, what are the most likely products? (A) aqueous Ca 2+ and OH¯ ions and gaseous PH 3 (B) aqueous Ca 2+ and OH¯ ions and aqueous H 3 PO 3 (C) solid CaH 2 and aqueous H 3 PO 3 (D) solid CaO and gaseous PH 3 5. A student plans to calculate the molar mass of an unknown gas from the mass of a measured volume of gas at a known temperature and pressure. To how many significant figures should the student report the molar mass if 175.0 mL of the gas weighs 1.0315 g at a temperature of 22 °C and pressure of 742 mmHg? (A) two (B) three (C) four (D) five
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6. The concentration of a colored substance is to be determined by measuring the absorbance of an aqueous solution of it and interpolating from a graph of absorbance versus concentration. Which procedural error will result in a concentration that is too high ? Procedural Mistakes I. rinsing the cuvette with water just before filling it with the unknown solution II. measuring the absorbance of the unknown solution at a wavelength other than its maximum III. using a cuvette for the unknown solution that has a slightly longer path length than you thought it had (A) I only (B) III only (C) I and II only (D) II and III only 7. What is the density (in g mL¯ 1 ) of a 3.60 M aqueous sulfuric acid solution that is 29.0% H 2 SO 4 by mass? (A) 1.22 (B) 1.45 (C) 1.64 (D) 1.88 8. Calculate the volume of 0.110 M copper(II) nitrate solution that can be prepared by dissolving 33.29 g of copper(II) nitrate trihydrate in sufficient distilled water. The molar mass of Cu(NO 3 ) 2 . 3 H 2 O equals 241.6 g mol¯ 1 (A) 0.50 L (B) 1.25 L (C) 2.50 L (D) 3.75 L 9. In alkaline solution, chlorine disproportionates to form chloride, Cl¯, and chlorate, ClO 3 ¯, ions. What is the ratio of chloride ions to chlorate ions formed? (A) one to one (B) three to one (C) five to one (D) seven to one 10. What is the formula of a substance with mass percentages of 35.97% for S, 62.92% for O and 1.13% for H? (A) H 2 SO 3
Background image of page 2
(B) H 2 SO 4 (C) H 2 S 2 O 7 (D) H 2 S 2 O 8 11. When 1.20 g of sulfur is melted with 15.00 g of naphthalene, the solution freezes at 77.2 C. What is the molar mass of this form of sulfur.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 14

1995 nat - U.S. National Chemistry Olympiad 1995 National...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online