C u ( O H ) 2. N i ( N O 3 ) 2. N a m e C a t i o n Cation A n i o n A n i o n

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1 Name Exam 3 Page 1 AQUEUS SLUTINS 1. (8 points) Names, formulas, and water-solubility of compounds. N a m e F o r m u l a Soluble in Water? Ammonium chloride N H 4 C l y e s C u ( H N i ( N 3 Iron(III) carbonate Sodium phosphate 2. (6 points) Ions and ion concentrations N a m e C a t i o n Cation A n i o n A n i o n Conc (M) Conc (M) 0.12 M i r o n ( I I ) c h l o r i d e C l 3.6 M N a 2 S 4 N a + XIDATIN-REDUCTIN REACTINS 1. (4 points) Specify the oxidation number for each of the underlined atoms. ( a ) HN 3 N = ( b ) N a 2 S 4 Na = and S = ( c ) S S = 2. (8 points) The following is a balanced, net ionic equation for the reaction of dichromate ion with tin(ii) ion. C r (aq) + 3 Sn 2 + (aq) + 14 H + (aq) 2 Cr 3 + (aq) + 3 Sn 4 + (aq) + 7 H 2 (l) ( a ) The substance oxidized is and the substance reduced is ( b ) The reducing agent is

2 Name Exam 3 Page 2 BALANCING EQUATINS & BASIC STICHIMETRY 1. (8 points) Balance equations for the following reactions: ( a ) Decomposition of ammonium nitrate NH 4 N 3 (s) N 2 (g) + H 2 (g) + 2 (g) ( b ) Combustion of octane. C 8 H 1 8 (liq) + 2 (g) H 2 (g) + C 2 (g) 2. (8 points) Iron ore is reduced to iron metal with carbon. 2 Fe 2 3 (s) + 3 C(s) 4 Fe(s) + 3 C 2 ( g ) ( a ) If 6.2 moles of Fe 2 3 (s) are reduced, moles of C(s) are needed, and moles of Fe are produced. ( b ) If you obtain 579 g of Fe from this reaction, but you should have obtained 1026 g, the percent yield is % ( c ) If you begin this process with 6.2 mol Fe 2 3 and 10.0 mol of C, the limiting reactant is. 3. (6 points) Ethanol (C 2, molar mass = 46 g/mol) burns in air according to the balanced equation. C 2 (g) (g) 2 C 2 (g) + 3 H 2 ( g ) If you burn 23 g of ethanol, what mass of water is formed? ( a 7 g H 2 ( b ) 90 g H 2 ( c ) 108 g H 2 ( d ) g H 2 If 130 g of C 2 (g) are formed, what mass of C 2 (g) was burned? ( a ) 36 g C 2 ( g ) ( b ) 68 g C 2 ( g ) ( c ) 78 g C 2 ( g ) ( d ) 136 g C 2 ( g )

3 Name Exam 3 Page 3 SLUTIN CNCENTRATINS AND SLUTIN STICHIMETRY 1. (3 points) You need to make 300 ml of an aqueous solution of M ammonium chloride (molar mass = 53.5 g/mol). How much solid ammonium chloride should you add? ( a ) 3.77 g ( b ) 41.9 g ( c ) 53.5 g ( d ) 68.3 g 2. (3 points) You wish to make a M hydrochloric acid solution from 12.0 M hydrochloric acid (concentrated HCl). How much concentrated acid must you add to obtain a total volume of 100 ml of the dilute solution? ( a ) ml ( b ) 1.04 ml ( c ) 120 ml ( d ) 150 ml 3. (4 points) You have a M solution of magnesium acetate (molar mass = g/mol). The concentration of the acetate ion in the solution is M What volume of the M magnesium acetate solution contains 17.3 grams of the salt? ( a 5.1 ml ( b ) 39.8 ml ( c ) ( d ) 587 ml 4. (3 points) A 100.-mL sample of a soft drink containing citric acid re q u i res ml of M NaH to neutralize the acid completely. What mass of citric acid (molar mass = g/mol) does the soft drink sample contain? The reaction of citric acid and NaH is ( a ) g citric acid ( b ) g citric acid ( c ) 19.5 g citric acid ( d 10 g citric acid H 3 C 6 H 5 7 (aq) + 3 NaH(aq) N a 3 C 6 H 5 7 (aq) + 3 H 2 (l)

4 Name Exam 3 Page 4 4. (8 points) You react zinc chloride with ammonia and isolate a solid with the formula Zn(NH 3. To find out the value of x, first dissolve the sample in water. This releases the ammonia into the solution where it can be titrated with HCl. Z n ( N H 3 (s) Z n ( a q ) + x N H 3 ( a q ) In this experiment you titrate a g sample of Zn(NH 3 with ml of M HCl. The reaction occurring is N H 3 ( a q ) + HCl(aq) N H 4 C l ( a q ) Is the value of x equal to 2 or 4 in Zn(NH 3? You must show your work completely and clearly to obtain full credit.

5 Name Exam 3 Page 5 WRITING CHEMICAL EQUATINS 1. (19 points) Writing equations ( a ) Complete and balance, by giving correct formulas for the product, the equation for the exchange reaction involving sodium carbonate and iron(ii) a c e t a t e. _ N a 2 C 3 + F e ( C H 3 C 2 _ p ro d u c t s Is this reaction an ( a ) acid-base reaction ( b ) a precipitation reaction ( c ) a gas-forming reaction? ( b ) Complete and balance the following equation. Give formulas for the reactants that would have produced MgBr 2, C 2, and H 2. M g B r 2 + C 2 + H 2 re a c t a n t s ( c ) Write a balanced, net ionic equation for the reaction of potassium hydroxide (KH) and copper(ii) sulfate (CuS 4 ) ( d ) Describe what you would observe if you mix aqueous solutions of lithium nitrate and sodium hydroxide. Include in your answer whether or not you would see a gas and if the product or products precipitate. ( e ) Describe what you would observe if you mix aqueous solutions of manganese(ii) carbonate and phosphoric acid? Include in your answer whether or not you would see a gas and if the product or products precipitate. ( f ) You are asked to prepare a sample of aluminum nitrate. C i rcle the pair of reactants in the list below that you would mix to e pr p a re aluminum nitrate. Possible Reactants A l ( H ) 3 K H H N 3 N a C l A l C l 3 K C l C a ( N 3 H C l A l 2 ( C 3 ) 3 K A l ( S 4 K N 3 N H 3 Describe what you would see when the reactants are mixed. Include in your answer whether or not you would see a gas and if the product or products precipitate.

6 Name Exam 3 Page 6 THERMCHEMISTRY N T E : specific heat capacity values are found in Table 6.1 in Chemistry & Chemical Reactivity. ther required data is found in Chapter (3 points) A sample of solid tin (specific heat capacity = J/g-K) is heated with an electrical coil. If 54.3 Joules of energy are added to a 14.0 gram sample initially at 21.1 C, what is the final temperature of the tin? ( a ) 18.2 C ( b 9.4 C ( c ) 39.3 C ( d ) 42.2 C 2. (3 points) You mix 100 g of liquid A at 100 C with 100 g of another liquid, B, at 50 C. The final temperature of the mixture is 80 C. Which has the larger heat capacity, A or B? ( a ) Liquid A ( b ) Liquid B 3. (6 points) (Study Question 6.65) A 9.36-g piece of platinum is heated to 98.6 C in a boiling water bath and then dropped onto ice. When the metal s temperature has dropped to 0.0 C, it is found that 0.37 g of ice had melted. Part 1: What quantity of heat was transferred to the ice from the platinum? ( a ) 1.11 J ( b ) 90.0 J ( c ) 123 J ( d ) 333 J Part 2: What is the specific heat capacity of platinum? (If you did not get an answer to Part 1of the question, use 1000 J for Part 2. Check here if you use 1000 J for part 2.) ( a ) 0.13 J/g-K ( b ) 1.08 J/g-K ( c ) 11.7 J/g-K ( d ) 114 J/g-K ( e ) none of the above

7 Name Exam 3 Page 7 Substitute Question for Page 4: Cobalt(III) ion forms many compounds with ammonia. To find the formula of one of these compounds, you titrate the NH 3 in the compound with standardized acid. C o ( N H 3 C l 3 (aq) + x HCl(aq) x NH 4 + (aq) + Co 3 + (aq) + (x + 3) Cl - ( a q ) Assume that ml of M HCl is used to titrate g of Co(NH 3 C l 3. Is the value of x equal to 4 or 6?