hemistry 12 Exam 1 September 27, 2000 Form A 1. The chemical formula for sodium phosphate is: A. S 3P 4 B. NaP 3. Na 3P 4 D. S 2P 3 E. Na 2P 4 2. ow many protons, neutrons and electrons does 201 g 2+ have? A. 80 protons, 80 neutrons, 80 electrons B. 80 protons, 80 neutrons, 78 electrons. 80 protons, 121 neutrons, 82 electrons D. 121 protons, 80 neutrons, 78 electrons E. 80 protons, 121 neutrons, 78 electrons 3. An unknown liquid has a density of 2.14 g/cm 3. ow many mm 3 would a 6.42 mg sample of this liquid occupy if dispensed into an 10 mm 3 UV/VIS spectrophotometer cuvette? A. 3.00 mm 3 B. 0.300 mm 3. 0.0300 mm 3 D. 13.7 mm 3 E. None of the above 1 2
4. hoose the correct IUPA name for the compound whose structure is shown below: A. 2-ethyl-3,4-dimethylhexane B. 3,4-dimethyl-5-ethylhexane. 5-ethyl-3,4-dimethylhexane D. 4,5,6-trimethyloctane E. 3,4,5-trimethyloctane 3 3 2 3 2 3 2 3 5. Which one of the following molecules is the geometric isomer of cis-2-pentene? A B 3 2 2 2 cis-2-pentene D 2 2 3 2 3 E Both A and are geometrical isomers of cis-2-pentene. 2 3 3 3 2 3 2 2 2 3 6. Which one of the following hydrocarbons is unsaturated but does not react readily (via addition reaction) with Br 2 at room temperature? A. an alkane B. an alkene. an alkyne D. an aromatic E. None of the hydrocarbons fit this description. 7. Which one of the following molecules contains both an amine and a carboxylic acid functional group? (This molecule could be called an amino acid.) A B D E 2 2 N 2 3 2 3 2 2 3 N 2 3 N 2 3 2 3 3 N 2 3 4
8. The carbon backbone for a molecule is given below. What is the molecular weight of this compound? A. 114 g/mol B. 115 g/mol. 119 g/mol D. 120 g/mol E. 126 g/mol 9. Below is a segment of a polymer formed via an addition reaction. Which one of the following is the monomer that was used to form this polymer? 3 3 3 3 10. hoose the appropriate words to fill in the blanks. A condensation reaction between a and a will form an. A. amide, ester, alcohol B. amine, carboxylic acid, amide. alcohol, amine, amide D. alcohol, alcohol, ester E. alcohol, carboxylic acid, amide 11. ow many hydrogen atoms are contained in a block of ice that weigh 2.00 kg? A. 1.34 x 10 23 B. 4.34 x 10 28. 6.68 x 10 25 D. 1.34 x 10 26 E. 3.34 x 10 25 12. If 2.0 g of water are formed from the explosion of a hydrogen balloon, how many grams of oxygen from the surrounding air are consumed? (assume that all of the hydrogen reacts) A B 3 3 A. 1.78 g B. 3.56 g. 0.00350 g D. 2.00 g E. 1.00 g D E 3 3 3 2 3 13. If a single molecule of a compound weighs 62.1 amu, how many moles of the compound are found in 6.00 g of material? A. insufficient information given. B. 373. moles. 0.846 moles D. 1.242 moles E. 0.0966 moles 3 5 6
14. Methanol is produced on a large scale by the reaction of carbon monoxide and hydrogen gases. If 10.0 kg of are reacted with 1.00 kg of 2, how many kg of methanol are produced? A. 7.94 kg B. 11.0 kg. 11.4 kg D. 2.38 kg E. 8.81 kg + 2 2 3 15. Glycerin has a weight percent composition of 52.1 %, 8.75 %, and 39.1 %. Which of the following is a possible molecular formula for glycerin? A. 3 6 3 B. 3 8 3. 3 6 2 D. 3 8 2 E. None of the above 16. ow many moles of water are there in 200. ml of water? (Assume that the density of water is 1.00 g/ml.) A. 0.111 mol B. 12.5 mol. 0.0900 mol D. 11.1 mol E. 3.60 10 2 mol 17. If an element named Whiznium had the following two isotopes: 74 Wh with 35% isotopic abundance and 76 Wh with 65% abundance, what would its atomic weight be? A. 74.0 B. 75.3. 74.7 D. 76.0 E. 75.0 ----------------------------------------------------------------------------------------------------- 7 18. Which of these reactions will form a precipitate in water? A. Mg( ) 2 + 2 l Mg(l) 2 + 2 2 B. Mg() 2 + (N 4) 2S 4 MgS 4 + 2 N 3 + 2 2. a 3 + 2 l al 2 + 2 + 2 D. l + 3K 3 + Kl E. Ba(N 3) 2 + K 2S 4 BaS 4 + 2 KN 3 19. ow many moles of ions are there in 1.0 L of 0.20 M Al 2(S 4) 3? A. 0.40 B. 1.0. 6.0 D. 2.0 E. 0.020 20. Stomach acid in gastric juice is hydrochloric acid. A 10.00 ml sample of gastric juice required 115.00 ml of 0.200 M K solution for neutralization during a titration. What was the molar concentration of l in gastric juice? A. 6.90 M B. 2.76 M. 0.0500 M D. 2.30 M E. 0.0200 M 21. When aqueous solutions of Fe 2(S 4) 3 (aq) and Pb(N 3) 2(aq) are mixed, an insoluble salt forms. Which of the following reactions is the correct net ionic equation that describes this reaction? A. 2Fe +3 (aq)+ 3S 2 4 (aq) + 3Pb 2+ (aq)+ 6N 3 (aq) Fe +3 (aq)+ 3S 2 4 (aq) + 3Pb 2+ (aq)+ 6N 3 (aq) B. Fe +3 (aq)+ S 2 4 (aq) + Pb 2+ (aq) + 3N 3 (aq) Fe(N 3) 3(s) + PbS 4(s). Fe +3 (aq) + 3N 3 (aq) Fe(N 3) 3(s) D. Pb 2+ (aq)+ 2N 3 (aq) Pb(N 3) 2(s) E. Pb 2+ (aq)+ S 4 2 (aq) PbS 4(s) 8
22. Which of the following are weak electrolytes? 1. 3 ( 2 3 2) 2. 3Na 3. 6 12 11 (table sugar) 4. Nal 4 A. 1 and 2 are weak electrolytes B. 1 and 3 are weak electrolytes. 1, 2 and 3 are weak electrolytes D. 4 is the only weak electrolyte E. 1 is the only weak electrolyte 23. What is the concentration of bromide ions in a 0.15 M solution of iron (III) bromide? A. 0.15 M B. 0.30 M. 0.45 M D. 0.050 M E. 0.60 M 24. Magnesium burns in air to produce a bright white light and is often used in fireworks. The combustion of magnesium follows the thermochemical equation 26. When the equation for the complete combustion of heptane is balanced, the stoichiometric coefficient on the 2 product is: A. 5 B. 6. 7 D. 8 E. 9 ----------------------------------------------------------------------------------------------------- 27. Which one of the following molecules is a structural isomer of octane? A B 2 3 3 2 2 2 2 3 2 2 2 2 3 2Mg(s) + 2(g) 2 Mg(s) o = 1203 kj ow much heat is liberated (in kj) by the combustion of 6.54 g of magnesium? A. 324 kj B. 53.0 kj. 162 kj D. 620 kj E. 101 kj 25. Which one of the following statements in reference to the following equation is false? 2u(s) + 2(g) 2u(s) o = 310 kj D 2 2 3 2 2 3 3 3 E 2 3 2 2 3 A. The reverse reaction is endothermic. 3 2 2 3 2 3 2 3 B. u(s) + 1/2 2(g) u(s) o = 155 kj. 2u(s) + 2(l) 2u(s) o = 310 kj D. 4u(s) + 2 2(g) 4 u(s) o = 620 kj E. The enthalpy change for the reverse reaction is +310 kj. 9 10
Answer Key: Form A 1 2 E 3 A 4 E 5 A 6 D 7 D 8 D 9 E 10 B 11 D 12 A 13 E 14 A 15 B 16 D 17 B 18 E 19 B 20 D 21 E 22 E (1/2 A) 23 24 25 26 27 11 12