4) Please indicate whether each of the following units are intensive or extensive. a) Density Intensive Extensive. b) Temperature Intensive Extensive

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1 EXAM ONE Nomenclature Balancing Reactions Protons, Neutrons, Electrons Natural Abundance Solubility Rules Net Ionic Reactions Atom, Mole, Gram Conversions Empirical Formulas Solution Chemistry / Molarity

2 1) What do the terms T.C. and T.D. mean? T.C. = T.D. = 2) A student did several runs to find the percentage of oxygen in the air. The data is given below, Run # Percentage Oxygen % % % % What is the average percentage of oxygen for this experiment? Express your answer to the correct number of significant figures. Later the student found that the percentage of oxygen in the air was actually 21.0%. The students data was, a) Accurate b) Precise c) Accurate and Precise d) Neither accurate nor precise 3) Circle the answer which expresses the result of the following calculation to the correct number of significant figures ) Please indicate whether each of the following units are intensive or extensive. a) Density Intensive Extensive b) Temperature Intensive Extensive c) Mass Intensive Extensive d) Energy Intensive Extensive 5) The units of energy used in this class will be the Joule (J). Using the basic units of mass, length, and time, give the definition of a joule.

3 6) Name the following compounds, a) Al 2 Se 3 b) XeF 4 c) Fe 2 (SO 4 ) 3 d) Cu 2 S e) CuSO 4 f) Ga(NO 3 ) 3 g) N 2 O 5 h) (NH 4 ) 2 SO 4 i) P 2 S 4 j) WCO 3 7) Give the formula of the following compounds, a) Beryllium Iodide b) Sulfur Hexafluoride c) Copper (I) Phosphate d) Iron (III) Sulfate e) Carbonic acid 8) Predict the charge(s) for each of the following atoms. Sr = Nb = Sn = Cd = Au = Re = 9) Predict the charge on the italicized element in each compound, Pd(ClO 4 ) 4 CH 2 O KMnO 4 Na 3 AsO 4 10) Give the product for each of the following reactions. Al + S ---> C + Br 2 ---> S + F 2 ---> P + O 2 --->

4 11) Balance the following reactions, a) FeS + O > Fe 3 O 4 + SO 3 b) Cl 2 + CH > CHCl 3 + HCl c) P 2 O 5 + H 2 O > H 3 PO 4 d) H 2 SO 4 + Al(OH) > Al 2 (SO 4 ) 3 + H 2 O e) Zn(ClO 4 ) 2 + K 2 S -----> ZnS + KClO 4 f) AlCl 3 + H 2 O > Al(OH) 3 + HCl 12) Write the balanced NET ionic reaction for each of the following; Ca(NO 3 ) 2 + H 3 PO 4 (NH 4 ) 2 S + ZnSO 4 AgNO 3 + NaCH 3 CO 2 NH 4 OH + H 2 S 13) Fill in the blanks. Symbol Atomic # # of Neut. # of Prot. # of Elect. Mass# 35 Cl 17 Symbol Atomic # # of Neut. # of Prot. # of Elect. Mass# 23 Na ) What is the mass percentage of copper in CuSO 4? 15) Copper is made up of two isotopes 63 Cu and 65 Cu and they weigh g and g respectively. If the average natural abundance mass of copper is g, calculate the percentage of 63 Cu and 65 Cu in naturally abundant copper.

5 16) When I went to write this problem I looked at the periodic table and saw that Rubidium had a mass of Since the mass of all isotopes are even (or nearly so) and this average was uneven I knew immediately that rubidium had to have two major isotopes. When I looked up the isotopes sure enough there were two of them but my book had the mass of only one. Instead of a mass the other isotope had a β- by it, which is clearly wrong. The table I found is given below. Could you please use the data in the table so I can fix my book (I'm not kidding, my book is wrong). Isotope %Natural Abundance Mass Rb(average) Rb Rb β- (wrong) 17) Using the solubility rules predict whether the following compounds are soluble or insoluble Na 2 SO 4 Soluble Insoluble FeBr 3 Soluble Insoluble Zr(CH 3 CO 2 ) 4 Soluble Insoluble CaS Soluble Insoluble PbCl 2 Soluble Insoluble ZnSO 4 Soluble Insoluble 18) How many atoms of sulfur (S) are there in 129 grams of FeS? 19) How many moles of copper are there in 10 grams of CuSO 4? 20) How many grams of sulfur are needed to react with 10 grams of iron to make Fe 3 S 4? 21) When KI and Pb(NO 3 ) 2 are mixed a yellow solid is formed. How many grams of KI are required to react with 30 grams of Pb(NO 3 ) 2, and how many grams of solid will form? What is the formula of the solid? 22) How much solid will form when 100 ml of 0.75M Pb(NO 3 ) 2 is added to 20 ml of 4 M KI?

6 23) How many moles of NH 3 will be produced when 6.70 mol of CeCl 3 are produced according to the following reaction? Ce 2 O 3 + 6NH 4 Cl --> 2CeCl 3 + 3H 2 O + 6NH 3 24) When a 10.0 g sample of an unknown organic acid is subjected to combustion analysis 21.2 grams of CO 2 and 3.25 g of H 2 O are produced. Upon further analysis it was found that the acid was 38.55% oxygen by mass. What is the empirical formula of the acid? 25) How many milliliters of 5 M CuSO 4 and water must you use to make 300 ml of 0.40 M CuSO 4? 26) When 25 grams of KI are added to 100 grams of Hg(NO 3 ) 2 a solid forms. What is the net ionic reaction? How much solid will form?

14 Chem Balancing - Practice Problems 1) Complete and/or balance the following reactions, a) FeS + O > Fe 3 O 4 + SO 3 b) CO 2 + H 2 O > CH 4 + O 2 c) P 2 O 5 + H 2 O > H 3 PO 4 d) Cl 2 + CH > CHCl 3 + HCl e) H 2 SO 4 + Al(OH) > Al 2 (SO 4 ) 3 + H 2 O f) NH 3 + O > NO + H 2 O g) H 2 S + O > H 2 O + SO 3 h) Pb(NO 3 ) 2 + H 3 AsO > PbHAsO 4 + HNO 3 i) Na + H 2 O ----> j) Li + N > k) C + Cl > l) CaCl 2 + (NH 4 ) 3 PO > m) C 3 H 8 O + O > o) CaCl 2 + H 3 PO 4 2) Write the formulas for the following compounds a) Titanium (IV) Chloride b) Tetraphosphorous decaoxide c) Sodium Carbonate d) Calcium Fluoride e) Iron (III) Nitrate f) Iodine Pentafluoride g) Aluminum Hydroxide

15 3) Please provide names for the following compounds. a) ZrO 2 b) (NH 4 ) 3 PO 4 c) Na 2 S d) SeF 4 e) CCl 4 f) CaCO 3 g) Co 2 O 3 4) Please write the product formed and balance each reaction a) P + O > b) Mg + N > c) Sc + S > d) Li + N > e) N 2 + H > 5) Please write the net ionic reaction that occurs when the following compounds are mixed. Barium Nitrate and Ammonium Carbonate Aluminum Nitrate and Sodium Hydroxide Lead Acetate and Potassium Iodide Silver (I) Nitrate and Sodium Dichromate Mercury (I) Perchlorate and Sodium Chloride Ammonium Phosphate and Calcium Chloride Phosphoric acid and Ammonium Hydroxide 6) Please complete and balance the following reactions when the each compound is combusted with oxygen. Fe 2 S 3 NH 3 NaCN CH 3 SH AgCH 3 CO 2

16 7) When a 10.0 gram sample of an unknown organic acid is subjected to combustion analysis, 21.2 grams of Co2 and 3.25 grams of H2O are produced. What is the empirical formula of the compound? 8) An 11.0 gram sample of a solid unknown was burned in oxygen producing 5.00 grams of water and grams of carbon dioxide. What is the empirical formula of the compound? 9) When a 15.0 gram sample of an acid is subjected to combustion analysis, grams of carbon dioxide and grams of water are formed. What is the empirical formula of the compound? 10) A gram sample of an organic acid was combusted in oxygen and produced grams of carbon dioxide and grams of water. What is the empirical formula of the compound?

17 Chem Balancing - Practice Problems 1) Complete and/or balance the following reactions, a) 3 FeS + 13/2 O > Fe 3 O SO 3 b) CO H 2 O > CH O 2 c) P 2 O H 2 O > 2 H 3 PO 4 d) Cl 2 + CH > CHCl 3 + HCl e) 3 H 2 SO Al(OH) > Al 2 (SO 4 ) H 2 O f) 2 NH O > N 2 O H 2 O g) H 2 S + 2 O > H 2 O + SO 3 h) Pb(NO 3 ) 2 + H 3 AsO > PbHAsO HNO 3 i) 2 Na + 2 H 2 O ----> 2 NaOH + H 2 j) 6 Li + N > 2 Li 3 N k) C + 2 Cl > CCl 4 l) 3 CaCl (NH 4 ) 3 PO > Ca 3 (PO 4 ) NH 4 Cl m) C 3 H 8 O + 9/2 O > 3 CO H 2 O o) 3 CaCl H 3 PO > Ca 3 (PO 4 ) HCl 2) Write the formulas for the following compounds a) Titanium (IV) Chloride TiCl 4 b) Tetraphosphorous decaoxide P 4 O 10 c) Sodium Carbonate Na 2 CO 3 d) Calcium Fluoride CaF 2 e) Iron (III) Nitrate Fe(NO 3 ) 3 f) Iodine Pentafluoride IF 5 g) Aluminum Hydroxide Al(OH) 3

18 3) Please provide names for the following compounds. a) ZrO 2 Zirconium (IV) Oxide b) (NH 4 ) 3 PO 4 Ammonium Phosphate c) Na 2 S Sodium Sulfide d) SeF 4 Selenium Tetrafluoride e) CCl 4 Carbon Tetrachloride f) CaCO 3 Calcium Carbonate g) Co 2 O 3 Cobalt (III) Oxide 4) Please write the product formed and balance each reaction a) 4 P + 5 O > 2 P 2 O 5 b) 3 Mg + N > Mg 3 N 2 c) 3 Sc + 3/8 S > Sc 2 S 3 d) 6 Li + N > 2 Li 3 N e) N H > 2 NH 3 5) Please write the net ionic reaction that occurs when the following compounds are mixed. Barium Nitrate and Ammonium Carbonate Ba 2+ + CO > BaCO 3 Aluminum Nitrate and Sodium Hydroxide Al OH > Al(OH) 3 Lead Acetate and Potassium Iodide Pb I > PbI 2 Silver (I) Nitrate and Sodium Dichromate 2 Ag + + Cr 2 O > Ag 2 Cr 2 O 7 Mercury (I) Perchlorate and Sodium Chloride Hg Cl > Hg 2 Cl 2 Ammonium Phosphate and Calcium Chloride 3 Ca PO > Ca 3 (PO 4 ) 2 Phosphoric acid and Ammonium Hydroxide H + + OH > H 2 O 6) Please complete and balance the following reactions when the each compound is combusted with oxygen. Fe 2 S O > Fe 2 O SO 3 2 NH O > N 2 O H 2 O 2NaCN + 5 O > Na 2 O + 2 CO 2 + N 2 O 5 CH 3 SH + 7/2 O > CO H 2 O + SO 3 2 AgCH 3 CO O > Ag 2 O + 4 CO H 2 O

19 7) When a 10.0 gram sample of an unknown organic acid is subjected to combustion analysis, 21.2 grams of CO 2 and 3.25 grams of H 2 O are produced. What is the empirical formula of the compound? 21.2 g CO 2 = mol CO 2 ==> mol C mol C x 12 g/mol = g C 44 g/mol mol H x 1 g/mol = g H g Total 3.25 g H 2 O = mol H 2 O ==> mol H 10 g g = g of oxygen 18 g/mol g O = mol O 16 g/mol mol C = 2 C mol H = 1.5 H mol O 1 O mol O 1 O The formula is C 2 H 1.5 O but you cannot have a fraction so, 2(C 2 H 1.5 O) = C 4 H 3 O 2 8) An 11.0 gram sample of a solid unknown was burned in oxygen producing 5.00 grams of water and grams of carbon dioxide. What is the empirical formula of the compound? g CO 2 = mol CO 2 ==> mol C mol C x 12 g/mol = g C 44 g/mol mol H x 1 g/mol = g H g Total 5.00 g H 2 O = mol H 2 O ==> mol H 11 g g = g of oxygen 18 g/mol g O = mol O 16 g/mol mol H = 1.5 H mol O = 1 O mol C 1 C mol C 1 C The formula is CH 1.5 O but you cannot have a fraction so, 2(CH 1.5 O) = C 2 H 3 O 2

20 9) When a 15.0 gram sample of an acid is subjected to combustion analysis, grams of carbon dioxide and grams of water are formed. What is the empirical formula of the compound? g CO 2 = mol CO 2 ==> mol C mol C x 12 g/mol = g C 44 g/mol mol H x 1 g/mol = g H g Total g H 2 O = mol H 2 O ==> mol H 15 g g = g of oxygen 18 g/mol g O = mol O 16 g/mol mol C = 1.5 C mol H = 3 H mol O 1 O mol O 1 C The formula is C 1.5 H 3 O but you cannot have a fraction so, 2(C 1.5 H 3 O) = C 3 H 6 O 2 10) A gram sample of an organic acid was combusted in oxygen and produced grams of carbon dioxide and grams of water. What is the empirical formula of the compound? g CO 2 = mol CO 2 ==> mol C mol C x 12 g/mol = g C 44 g/mol mol H x 1 g/mol = g H g Total g H 2 O = mol H 2 O ==> mol H g g = g of oxygen 18 g/mol g O = mol O 16 g/mol mol C = 3 C mol H = 6 H mol O 1 O mol O 1 C The formula is C 3 H 6 O.

21 Concentration Problems 1) When ammonium sulfide is added to silver nitrate solid silver sulfide is formed according to the following reaction; 2 Ag(NO 3 ) + (NH 4 ) 2 S ----> Ag 2 S + 2 NH 4 NO 3 a) If 25.0 ml of 0.10 M Ammonium sulfide is added to 60.0 ml of 0.10 M silver nitrate how much silver sulfide will form? b) Calculate the final concentration of the silver after all the precipitate (solid) has formed. 2) When 75 ml of 0.20M Na 3 PO 4 is added to 125 ml of 0.30 M Zn(NO 3 ) 2 a white solid forms. a) Please write the NET ionic reaction that occurred. b) How many grams of solid were made? c) What is the concentration of all the ions left in solution? 3) When 100 ml of 0.40M NaOH is added to 75 ml of 0.6 M Zn(NO 3 ) 2 a white solid forms. a) Please write the NET ionic reaction that occured. b) How many grams of solid were made? c) What is the concentration of all the ions left in solution? 4) How many grams of solid will form, and what is the concentration of all ionic species left in solution when 125 ml of 0.2 M Pb(NO 3 ) 2 and 50 ml of 0.60 M KI are mixed together? 5a) Write the NET IONIC reaction for the addition of 75 ml of 3 M NaOH with 100 ml of 2M BaCl 2. b) How much solid will form? c) What is the concentration of the chloride ion after the reaction is complete? 6) A student took 25 ml of a concentrated H 2 SO 4 solution and added 225 ml to it to make a more dilute solution. Afterwards 35 ml of the diluted H 2 SO 4 solution was titrated with 22.7 ml of 1.5 M NaOH to the phenophthalein endpoint. What was the concentration of the original (concentrated) H 2 SO 4? 7) When 150 ml of 1 M CaCl 2 is added to 100 ml of 2.5 M Hg(NO 3 ) 2 a precipitate forms. Please write the balance NET ionic reaction for the formation of the precipitate. b) What is the limiting reagent? c) How many grams of precipitate will form? d) What is the concentration of all the ions left in solution?

28 Chemistry 120 Name First Exam October 14, 1988 CLOSED BOOK EXAM - No books or notes allowed. ALL work must be shown for full credit. You may use a calculator. Question Credit 1 (10) 2(10) 3(10) 4(12) 6(20) 7(20) 8(8) TOTAL 1) Balance the following reactions; a) NH 3 + O > NO + H 2 O b) H 2 S + O > H 2 O + SO 3 c) Pb(NO 3 ) 2 + H 3 AsO > PbHAsO 4 + HNO 3 2) Write the formulas for the following compounds. a) Chromium (III) oxide b) Carbonic acid c) Cesium sulfate d) Diphophorous pentoxide

29 3) Calculate the average of the following set of data to the correct number of significant figures Average = 4) Given 4.0 grams of C 2 H 4 and 18.0 grams of Cl 2 in the following reaction how many grams of HCl can form? C 2 H Cl > C 2 H 3 Cl 3 + HCl grams 6) Consider the compound Yttrium (III) Chloride. Using your periodic table, answer the following questions concerning the metal portion of the compound. Atomic symbol = Mass number = Atomic number = Number of protons = Number of neutrons = Number of electrons = Yttrium is a metal.

30 7) An 11.0 gram sample of a solid unknown was burned in oxygen producing 5.00 grams of water and grams of carbon dioxide. What is the empirical formula of the compound? 8) How many atoms of oxygen are there in 19.5 grams of FeSO 4? 9a) What does TC and TD mean when found on glassware? 9b) What is the difference between accuracy and precision (define each)? 9c Which is the more accurate piece of glassware, a Mohr pipet or a graduated cylinder?

31 Chemistry 120 Name First Exam October 14, 1988 CLOSED BOOK EXAM - No books or notes allowed. ALL work must be shown for full credit. You may use a calculator. Question Credit 1 (10) 2(10) 3(10) 4(12) 6(20) 7(20) 8(8) TOTAL 1) Balance the following reactions; a) 2 NH 3 + 5/2 O > 2 NO + 3 H 2 O b) H 2 S + 2 O > H 2 O + SO 3 c) Pb(NO 3 ) 2 + H 3 AsO > PbHAsO HNO 3 2) Write the formulas for the following compounds. a) Chromium (III) oxide Cr 2 O 3 b) Carbonic acid H 2 CO 3 c) Cesium sulfate Cs 2 SO 4 d) Diphophorous pentoxide P 2 O 5

32 3) Calculate the average of the following set of data to the correct number of significant figures Total = Average = /5 = but on 2 sig figs so, Average = 34 4) Given 4.0 grams of C 2 H 4 and 18.0 grams of Cl 2 in the following reaction how many grams of HCl can form? C 2 H Cl > C 2 H 3 Cl 3 + HCl 6) Consider the compound Yttrium (III) Chloride. Using your periodic table, answer the following questions concerning the metal portion of the compound. Note: YCl 3 = Y 3+ Atomic symbol = Y Atomic number = 39 Number of protons = 39 Number of neutrons = 50 Number of electrons = 36 Yttrium is a Transition metal. 7) An 11.0 gram sample of a solid unknown was burned in oxygen producing 5.00 grams of water

33 and grams of carbon dioxide. What is the empirical formula of the compound? 8) How many atoms of oxygen are there in 19.5 grams of FeSO 4? 9a) What does TC and TD mean when found on glassware? TC = To Contain - Graduated cylinders TD = To Deliver - Pipets and Burets 9b) What is the difference between accuracy and precision (define each)? Accuracy is how close the experiment value is to the accepted value Precision is how close each experimental value is to one another. 9c Which is the more accurate piece of glassware, a Mohr pipet or a graduated cylinder? A Mohr pipet

1) What is the volume of a tank that can hold Kg of methanol whose density is 0.788g/cm 3?

1) What is the volume of a tank that can hold Kg of methanol whose density is 0.788g/cm 3? 1) Convert the following 1) 125 g to Kg 6) 26.9 dm 3 to cm 3 11) 1.8µL to cm 3 16) 4.8 lb to Kg 21) 23 F to K 2) 21.3 Km to cm 7) 18.2 ml to cm 3 12) 2.45 L to µm 3 17) 1.2 m to inches 22) 180 ºC to K