Chapter 13 1. Which of the following compounds is a strong electrolyte? a. NH 4Cl b. NaCl c. NaC 2H 3O 2 d. HCl e. All of the above 2. A solution that is 13.58% by mass of sugar contains 13.75 grams of sugar dissolved in 87.5 grams of water. a. True b. False 3. How many grams of a 23.4% by mass NaF solution is needed if you want to have 1.33 moles of NaF? a. 239 b. 31.1 c. 55.9 d. 13.1 4. Which of the following aqueous solutions would be expected to freeze at the lowest temperature? a. 1 molal KNO 3 b. 1 molal NaCl c. 1 molal CaCl 2 d. 1 molal C 6H 12O 6 (fructose) e. All of the solutions would freeze at the same temperature 5. 13.51 g of table sugar (C 12H 22O 11) is dissolved in 241.9 ml of water (density 0.997 g/ml). The final volume is 250.0 ml. The final volume is 250.0 ml. Calculate the boiling point for this solution.
Calculate the freezing point for this solution. Chapter 14 6. What are the products of the reaction between HBr (aq) and KOH (aq). 7. The titration of 25.00 ml of a 0.125 M HClO 4 solution required 24.02 ml of KOH to reach the endpoint. What is the concentration of the KOH? 8. A 25.00 ml sample of an HNO 3 solution is titrated with 0.102 M NaOH. The titration requires 28.52 ml to reach the equivalence point. What is the concentration of the HNO 3 solution? 9. In which solution is the [H 3O+] less than 0.250 M? a. 0.250 M HF (aq) b. 0.250 M HCHO 2 c. 0.250 M HC 2H 3O 2 d. All of these 10. In which solution is [H 3O+] less than 0.100 M? a. 0.100 M HCHO 2 (aq)
b. 0.100 M HClO 4 (aq) c. 0.100 M H 2SO 4 (aq) 11. In which solution is [OH-] equal to 0.100 M? a. 0.100 M NH 3 (aq) b. 0.100 M NaOH (aq) c. 0.100 M Ba(OH) 2 (aq) 12. Calculate [OH-] given [H 3O+] in each aqueous solution. [H 3O+] = 5.8 x 10-3 M. Classify this solution as acidic or basic. [H 30+] = 8.6 x 10-12 M. Classify this solution as acidic or basic. 13. What is the ph of a solution with [H 3O+] = 2.8 x 10-5 M? 14. What is [OH-] in a solution with a ph of 9.55? 15. What substance could you add to each solution to make it a buffer solution? *A buffer contains significant amounts of both a weak acid and its conjugate base*
0.100 M NaC 2H 3O 2 a. KC 2H 3O 2 b. HCl c. NaOH d. HC 2H 3O 2 0.500 M H 3PO 4 a. KOH b. NaH 2PO 4 c. Ag 3PO 4 d. HCl 16. A buffer contains HCHO 2 (aq) and KCHO 2 (aq). Summarize the action of this buffer. 17. For [OH-] = 7.8 x 10-5 M, determine the ph. State whether the solution is acidic or basic. Previous material 1. 19.667 (5.4 x 0.916) complete with the correct number of significant figures. 2. A chemist needs a 23.5 kg sample of ethanol for a large-scale reaction. What volume in liters of ethanol should the chemist use? The density of ethanol is 0.789 g/cm3.
3. Gallium is a solid metal at room temperature but melts at 29.9 o C. If you hold gallium in your hand, it melts from your body heat. How much heat must 2.5 g of gallium absorb from your hand to raise the temperature of the gallium from 25.0 o C to 29.9 o C? The specific heat capacity of gallium is 0.372 J/g o C. 4. Magnesium has three naturally occurring isotopes with masses of 23.99, 24.99, and 25.98 amu and natural abundances of 78.99%, 10.00%, and 11.01%. Calculate the atomic mass of magnesium. 5. Name each compound. SF 6 H 2S HC 2H 3O 2 6. Butane is a compound containing carbon and hydrogen used as a fuel in butane lighters. Its empirical formula is C 2H 5, and its molar mass is 58.12 g/mol. Find its molecular formula. 7. Write an equation for the precipitation reaction that occurs (if any) when solutions of sodium carbonate and copper(ii) chloride are mixed.
8. Write an equation for the precipitation reaction that occurs (if any) when solutions of lithium nitrate and sodium sulfate are mixed. 9. Consider this reaction occurring in aqueous solution. 2 HBr(aq) + Ca(OH) 2(aq) 2 H 2O(l) + CaBr 2(aq) Write a complete ionic and a net ionic equation for the reaction. 10. Write a molecular equation for the gas evolution reaction that occurs when you mix aqueous nitric acid and aqueous sodium carbonate. 11. Consider this reaction: Cu 2O(s) + C(s) 2 Cu(s) + CO(g) When 11.5 g of C are allowed to react with 114.5 g of Cu 2O, 87.4 g of Cu are obtained. Determine the limiting reactant, theoretical yield, and percent yield.
12. Ammonia reacts with oxygen according to the equation: 4 NH 3(g) + 5 O 2(g) 4 NO(g) + 6 H 2O Δ H rxn = -906 kj Calculate the heat (in kj) associated with the complete reaction of 155 g of NH 3. 13. Write an electron configuration for selenium and identify the valence and core electrons. 14. Predict the electron and molecular geometry of PCl 3. Draw a Lewis structure and predict if the molecule will be polar. 15. How many liters of oxygen gas form when 294 g of KClO 3 completely react in this reaction (which is used in the ignition of fireworks)? 2 KClO 3(s) 2 KCl(s) + 3 O 2(g) Assume that the oxygen gas is collected at P = 755 mmhg and T = 305 K.
16. Calculate the amount of water in grams that can be vaporized at its boiling point with 155 kj of heat. 17. Calculate the amount of ice in grams that, upon melting (at 0 o C), absorbs 237 kj of heat. 18. List these substances in order of increasing boiling point: H 2O, Ne, NH 3, NaF, SO 2