CHEM 104 Final Exam; Questions and Answers 100% Solved

CHEM 104 F inal Exam ; Questions and Answers 100% Solved How many moles of hydroxide ions are there in 25 mL of 0.010M solution of Ba(OH)2? a. 7.5 x 10 -1 mol b. 5.0 x 10 -1 mol c. 2.5 x 10 -1 mol d. 5.0 x 10 -4 mol e. 2.5 x 10 -4 mol Correct answer -d. 5.0 x 10 -4 mol What is the molarity of a solution that contains 46 grams of Na2SO4 (Mw = 142 g/mol) dissolved in enough water to make 750 mL of solution? a. 2.3M b. 0.60M c. 0.52M d. 0.43M e. 0.19M Correct answer -d. 0.43M Imagine that you go into the lab and measure 35 mL of a 0.60M stock solution. You pour the 35 mL of stock solution into a beaker and dilute the solution by adding another 35 mL of water. What is the molarity of the new solution? a. 1.2M b. 0.60M c. 0.30M d. 0.15M e. 0.040M Correct answer -c. 0.30M What is the correct expression for the equilibrium constant, K, for the following reaction? P4(s) + 5O2(g) ⇌ P4O10(s) Correct answer -K= 1/[O2]^5 CHEM 104 F inal Exam ; Questions and Answers 100% Solved If for a certain gas phase reaction mixture Q = 1, what can you say about the reaction? a. The reaction will proceed towards the product to achieve equilibrium. b. The equilibrium position will be determined by the value of K. c. The reaction will proceed to the left to achieve equilibrium. d. The reaction is already at equilibrium. e. The reaction will go to completion. Correct answer -b. The equilibrium position will be determined by the value of K. If we increase the volume of the container, then the equilibrium will _______ and the partial pressure of X2(g) will ____________. a. Shift to the left, decrease b. Shift to the left, increase c. Shift to the right, decrease d. Shift to the right, increase e. Not shift, not change Correct answer -a. Shift to the left, decrease If you decrease the temperature of this reaction the equilibrium will shift to the________ and the value of K will __________. a. right, not change b. right, decrease c. right, increase d. left, decrease e. left, increase Correct answer -c. right, increase Which of the following combinations represent a weak acid and weak base conjugate pair? a. HCl and NaCl b. KH2PO4 and Na3PO4 CHEM 104 F inal Exam ; Questions and Answers 100% Solved c. CH3COOH and KCH3COO d. both choice b and choice c e. choice a, choice b and choice c Correct answer -c. CH3COOH and KCH3COO What is the pH of 0.050M HClO4? a. 0.90 b. 1.3 c. 3.0 d. 7.0 e. 12.7 Correct answer -b. 1.3 What is the pH of 0.080M NH3? a. 1.1 b. 2.9 c. 8.8 d. 11.1 e. 12.9 Correct answer -d. 11.1 Which of the following three salts would be basic if dissolved in water? I. KNO2 II. NH4Cl III. Zn(NO3)2 a. I only b. II only c. III only d. I and II only e. all three Correct answer -a. I only