LISTA DE EXERCÍCIOS AULA 06/10/2016

Transcription

1 LISTA DE EXERCÍCIOS AULA 06/10/ Sodium hypochlorite, the active ingredient in Clorox, can be made by the following reaction: 2 NaOH(aq) + Cl 2 (g) NaCl(aq) + NaClO(aq) + H 2 O(l) If chlorine gas is bubbled continuously through a solution containing 60.0 g of NaOH, how many grams of NaClO can be produced, assuming the reaction goes to completion? 2- For the following unbalanced chemical equation: NiS + O 2 + HCl NiCl 2 + H 2SO 4 a) Write the balanced chemical equation for this reaction. b) What mass of NiCl 2 will be produced if g of NiS reacts? 3-Vanadium (V) oxide, V 2 O 5, can be reduced by zinc to form vanadium (II) oxide, V 2 O 2 and zinc oxide, ZnO. a) Write and balance the chemical equation for this process. b) What mass of vanadium (II) oxide can be produced from a mixture of grams of V 2 O 5 and grams of Zn? 4- Many binary compounds of phosphorus and sulfur have been prepared. Balance the following chemical equation for the preparation of P 4 S 5. (Hint: balance the S first.) P 4 S 3 + Br 2 P 4S 5 + PBr 3 What is the maximum quantity of P 4 S 5 that could be prepared from g of P 4 S 3 and ml of liquid bromine? (Density of bromine is 3.12 g/ml) 5- A 10.0 ml sample of concentrated sulfuric acid contains 17.7 g of H 2 SO 4. Determine the molarity of concentrated sulfuric acid. 6- Pure acetic acid (C 2 H 4 O 2 ) has a density of g/ml. Calculate the molarity

2 of pure (anhydrous) acetic acid. 7- A hydrochloric acid solution is prepared by dissolving 1.97g of hydrogen chloride gas in 27.3 ml of water and then diluting that mixture to a total volume of ml. Calculate the molarity of the resulting solution. 8- The concentration of NaClO in Clorox is M. Calculate the mass of NaClO present in 1.0 ml of Clorox. 9- A solution is prepared by dissolving x grams of potassium nitrate in water and diluting to a total volume of ml. Another solution is prepared by dissolving y grams of sodium chloride in water and diluting to a total volume of ml. Both solutions are then mixed together, giving a final concentration of KNO 3 of mol/l and a final concentration of NaCl of mol/l. Calculate x and y. 10- The toxic compound NCl 3 can be formed from the reaction of bleach (NaClO) with ammonia (NH 3 ): NaClO(aq) + NH 3 (aq) NCl 3 (l) + NaOH(aq) a) Write a complete, balanced, net ionic equation for this process. b) You accidentally pour 1.0 ml of Clorox into a large bucket of ammonia solution. What mass of NCl 3 can be produced if the reaction goes to completion? (Clorox is a molar solution of NaClO in water.) 11- A sample of calcium carbonate weighing 6.35 grams is placed in ml of 0.31M hydrochloric acid and allowed to react to form calcium chloride and carbon dioxide gas. Calculate the maximum mass of carbon dioxide gas that can be produced. 12- What volume of mol/l Ba(OH) 2 neutralize a 1.00-mL sample of 12.0 mol/l acetic acid? would be required to completely

3 13- A student has dissolved 87.5 grams of sodium hydroxide in 1.53 liters of water. This strongly basic solution must be neutralized before disposal. What volume of 1.27 mol/l HCl would be required to completely neutralize this solution? 14- Phosphoric acid can be neutralized by sodium hydroxide according to the equation: H 3 PO NaOH Na 3PO H 2 O a) What volume of M NaOH would be required to neutralize 5.00 ml of concentrated (14.8 M) phosphoric acid? 15- You are given 2.00 grams of a white solid and told that it is a mixture of NaCl and Na 2 CO 3. You dissolve the sample in water and titrate with HCl; complete neutralization requires 23.0 ml of 1.00 mol/l HCl: Na 2 CO HCl H 2CO NaCl Calculate the mass of Na 2 CO 3 in the unknown sample. 16- The equation: N 2 O 4 (g) 2 NO 2 (g) has an equilibrium constant K C of at 25 C. Calculate the equilibrium constant for the related reaction: NO 2 (g) ½ N 2 O 4 (g) 17- Nitrogen oxides are partly responsible for smog. Nitrogen monoxide, NO, is released from the burning of fossil fuels, and is oxidized by oxygen in the air to form brown nitrogen dioxide, NO 2 : 2NO(g) + O 2 (g) 2NO 2 (g) K P = at 25 C a) Calculate the value of K c for this reaction at 25 C. b) On a certain day, the partial pressures of NO, O 2, and NO 2 were as follows: P = 152 torr; P = 1.1 O2 NO 10-5 torr; P = NO2 torr. Calculate the value of Q, and determine if NO 2 will be produced or consumed under these conditions.

4 18- The decomposition of NOBr has an equilibrium constant K P = at 350 K: NOBr(g) NO(g) + ½Br 2 (g) a) Calculate the value of K c for this reaction at 350 K. b) A 2.00-liter flask contains 0.50 mol NOBr, 0.40 mol NO, and 0.20 mol Br 2 at 350 K. Calculate the reaction quotient Q, and determine if NOBr will be produced or consumed under these conditions. 19- Consider the decomposition of SO 2 Cl 2 at 600 K. SO 2 Cl 2 (g) SO 2 (g) + Cl 2 (g) ΔH = +67 kj/mol Predict the change in SO 2 Cl 2 concentration at equilibrium if you: i) add more SO 2 ; ii) decrease the volume of the flask iii) raise the temperature 20- In an investigation of the reaction: CO 2 + H 2 CO + H 2 O a chemist put 0.50 mol CO 2 and 0.50 mol H 2 into a 2.00 L flask and allowed them to reach equilibrium at 690 K. At equilibrium 0.38 mol CO 2 remained. What is the equilibrium constant for this reaction at 690 K? 21- Consider the equilibrium decomposition of SO 2 Cl 2 at 600 K: SO 2 Cl 2 (g) SO 2 (g) + Cl 2 (g) K C = 6.1 at 600 K A 1.00-liter evacuated flask is filled with moles of SO 2 Cl 2 Calculate the moles of each gas at equilibrium, and the total pressure. at 600 K. 22- For the following Bronsted-Lowry acid-base reactions, identify the reactant which is acting as an acid and the reactant acting as a base: HN 3 + NH 2OH NH 3 OH N 3 CN - + B(OH)3 HCN + BO(OH) 2 - Si(OH) 4 + C 6H 5 O - - SiO(OH)3 + C6 H 6 O

5 23- Calculate the ph of each of the following solutions. a) M KOH b) 0.020MHBr c) mol/l Ba(OH)2 d) mol/l KOH 24- A solution is prepared by mixing 500. ml of 0.10 M NaOH with 500. ml of M H 2 SO 4. a) Write the equation for the chemical reaction which will take place. b) Calculate the ph of the resultant solution. 25- Calculate the ph of a M solution of HF (K a = ) 26- Calculate the ph of a M solution of HIO 3. (K a = ) 27- Calculate the ph of a M solution of CH 3 NH 2. (K b = ) 28- Many home pools are disinfected by adding calcium hypochlorite, Ca(OCl) 2. The hydrolysis of the hypochlorite ion yields hypochlorous acid. Given that K a for HOCl = , calculate the ph of an M solution of calcium hypochlorite, Ca(OCl) 2.