a) ___Fe2(SO4)3 + _12__K(SCN)  __2__K3Fe(SCN)6 + _3__K2SO4b) Liquid Pentaboron nonahydride + oxygen gas  solid diborontrioxide + gaseous dihydrogen monoxide2 B5H9 (l) +12 O2 (g)  5 B2O3 (s) + 9 H2O (g)c) UO2 (s) + 4 HF (l)  UF4 (s) + 2 H2O (l)Chapter 2 and 3 Practice Worksheet key1. Two different compounds are formed by the elements carbon and oxygen. The first compound contains 42.9% by mass carbon and 57.1% by mass oxygen. The second compound contains 27.3% by mass carbon and 72.7% by mass oxygen. Show that the data are consistent with the Law of Multiple Proportions.The masses of oxygen in the two compounds that combine with a fixed mass of carbon should be in a whole-number ratio. In 100 g of the first compound (100 is chosen to makecalculations easier) there are 57.1 g O and 42.9 g C. The mass of O per gram C is: 57.1 g O / 42.9 g C = 1.33 g O per g C In the 100 g of the second compound, there are 72.7 g O and 27.3 g C. The mass of oxygen per gram of carbon is: 72.7 g O / 27.3 g C = 2.66 g O per g C Dividing the mass O per g C of the second (larger value) compound: 2.66 / 1.33 = 2 Which mean that the masses of oxygen that combine with carbon are in a 2:1 ratio. The whole-number ratio is consistent with the Law of Multiple Proportions. 2. Natural copper has an atomic mass of 63.55 amu. The two most common Isotopes of Cu are. 63Cu and 65Cu, which weighs 62.9295975 amu and 64.9277895 amu respectively. What are the relative abundances of these two isotopes in natural copper?63.55 amu = x (62.9295975 amu) + (1-x) 64.9277895 amuNatural abundance 63Cu = xNatural abundance 65Cu=1-x63.55 amu = (62.9295975 amu) x + 64.9277895 amu -64.9277895 amu (x) -1.3777895 amu= -1.998192 x X= 0.6895 x100 =69.0% 63Cu Natural abundance 65Cu= (1-0.6895)*100 = 31.0% 65Cu3. Phencyclidine (a.k.a. “angel dust”) is C17H25N. A sample picked up in a police drug raid is suspected of being this illicit drug; when tested, the sample was shown to have a percentage composition of 83.71% C, 10.42% H, and 5.61% N. Prove if this sample is phencyclidine. %C= (12.01*17)/(12.01*17+1.01*25+14.01)= 204.2/(204.2+25.2+14.01)= 204.2/243.4= 83.89% ~83.71%%H= 25.2/243.4= 10.4% ~ 10.42%%N= 14.01/243.4= 5.756%~ 5.61%4. An unknown contains C, H, O, and S. When a 5.000 g sample is combusted, it produces 4.731 g carbon dioxide, 2.419 g of water, and 3.441 g of sulfur dioxide.a. What is the empirical formula of the unknown?.731 g carbon dioxide x 12.01 g C = 1.290 g C x 1 mol C = 0. 1075 mol C 44.02 g CO2 12.01 g C2.419 g of water x 1 mol water x 2 mol H x 1.008 g H = 0.269 g = 0.269 mol H 18.02 g water 1 mol water 1 mol water3.441 g of sulfur dioxide x 32.06 g S = x 1 mol S = 0.054 mol S 65.06 g SO2 32.06 g S 5.000 g sample =1.290 g C + 0.269 g + 1.721 g S + grams oxygen grams oxygen =1.72 g O x 1 mol O = 0.1075 mol O 16.00 g O0.1075 mol O / 0.054 mol = 2 O0. 1075 mol C / 0.054 mol = 2 C0.269 mol H / 0.054 mol = 5 H0.054 mol S / 0.054 mol = 1 SC2H5SO2b. If the molar mass is determined to be 186 g, what is the molecular formula of the unknown?C2H5SO2 MM = 93.12 g/mol X = 186 g/93.12 g/mol = 2C4H10S2O45. Provide the name or chemical formula (as needed) for the following compounds.a. (NH4)2C2O4 ____ammonium oxalate__ a) Sodium monohydrogen phosphate__Na2HPO4_b. HClO2 (aq)__chlorous acid ____ b) Cesium hydride__CsH__c. CaSO3___Calcium sulfite________ c) Barium acetate___BaC2H3O2___d. AgCN_____silver cyanide______ d) Nickel (II) nitride__Ni3N2___e. HgBr2____mercury(II) bromide____ e) Stannic sulfide decahydrate__SnS2*10 H2O____f. K2CrO4___potassium chromate_____ f) Tetrarsenic decoxide_As4O10_____g. Fe(OH)2*6 H2O__Iron(II) hydroxide hexahydrate____g) Magnesium hydroxide___Mg(OH)2______h. I4O9___tetraiodine nonoxide____ h) Aluminum thiocyanate___Al(SCN)3____6. Magnesium reacts with oxygen to produce the ionic solid magnesium oxide (MgO). Which other elements would you predict would react with oxygen in a similar reaction?All the metals in the alkaline earth family will react in a similar manner. Be, Ca, Sr, Ba, Ra 7. Write if necessary and balance the following chemical equations:a) ___Fe2(SO4)3 + _12__K(SCN)  __2__K3Fe(SCN)6 + _3__K2SO4 b) Liquid Pentaboron nonahydride + oxygen gas  solid diborontrioxide + gaseous dihydrogen monoxide 2 B5H9 (l) +12 O2 (g)  5 B2O3 (s) + 9 H2O (g)c) UO2 (s) + 4 HF (l)  UF4 (s) + 2 H2O (l)d) Lead(II) acetate (aq) + rubidium bromide (aq)  rubidium acetate (aq) + solid lead(II) bromidePb(C2H3O2)2 (aq) + 2 RbBr (aq)  2 RbC2H3O2 (aq) + PbBr2 (s)8. A certain fertilizer is rated as 6.0 % nitrogen meaning that is contains 6.0 g of N in 100 g of fertilizer. The nitrogen is present in the form of ammonium phosphate, (NH4)3PO4. Calculate the mass of (NH4)3PO4 (in grams) that is present in 100 g of this fertilizer.(6.00 g N) (1 mole N / 14.01 g N) {1 mole (NH4)3PO4 / 3 mole N} = 0.143 mole (NH4)3PO4 {0.143 mole (NH4)3PO4} (149.1 g / mole) = 21. 3 g