Formula Mass and Molarity Calculations for Various Compounds, Slides of Chemistry

Download Formula Mass and Molarity Calculations for Various Compounds and more Slides Chemistry in PDF only on Docsity! 1. What is the formula mass of each species? a. ammonium chloride : NH4Cl ; 14.01(N)+1.01(H)x4+35.45(Cl) = 53.5 b. sodium cyanide : NaCN ; 22.99 (Na) + 12.01 (C) + 14.01 (N) = 49.01 c. magnesium hydroxide : Mg(OH)2 ; 24.31 (Mg) + 2x (16.00 (O) + 1.01 (H)) = 58.33 d. calcium phosphate : Ca3(PO4)2 ; 3 x 40.08 (Ca) + 2x (30.97 (P) + 4x16.00(O)) = 310.18 e. lithium carbonate : Li2CO3 ; 2x 6.94 (Li) + 12.01 (C) + 3x 16.00 (O) = 73.89 f. hydrogen sulfite ion : HSO3 ; 1.01 (H) + 32.07 (S) + 3x 16.00 (O) = 81.08 2. What is the molecular or formula mass of each compound? a. potassium permanganate : KMnO4 ; 39.1 (K) + 54.94 (Mn) + 4x 16.00 (O) = 158.04 b. sodium sulfate : Na2SO4 ; 2x 22.99 (Na) + 32.07 (S) + 4x 16.00 (O) = 142.05 c. hydrogen cyanide : HCN ; 1.01 (H) + 12.01 (C) + 14.01 (N) = 27.03 d. potassium thiocyanate : KSCN ; 39.1 (K) + 32.07 (S) + 12.01 (C) + 14.01 (N) = 97.19 e. ammonium oxalate : (NH₄)₂C₂O₄ ; 2x (14.01 (N) + 4x 1.01 (H)) + 2x 12.01 (C) + 4x 16 (O) = 124.12 f. lithium acetate : C2H3LiO2 ; 2x 12.01 (C) + 3x 1.01 (H) + 6.94 (Li) + 2x 16 (O) = 65.99 3. How many moles are in each of the following? a. 10.76 g of Si x 1 mol Si / 28.09 g Si = 0.383 mol Si b. 8.6 g of Pb x 1 mol Pb / 207.20 g Pb = 0.042 mol Pb c. 2.49 g of Mg x 1 mol Mg / 24.32 g Mg = 0.102 mol Mg d. 0.94 g of La x 1 mol La / 138.91 g La = 0.00677 mol La e. 2.68 g of chlorine gas x 1 mol Cl2 / 70.9 g Cl2 = 0.0378 mol Cl2 f. 0.089 g of As x 1 mol As / 74.92 g As = 0.00119 mol As 4. How many moles are in each of the following? a. 8.6 g of CO2 x 1 mol CO2 / 44.01 g CO2 = 0.195 mol CO2 b. 2.7 g of CaO x 1 mol CaO / 56.08 g CaO = 0.048 mol CaO c. 0.89 g of KCl x 1 mol KCl / 74.55 g KCl = 0.0119 mol KCl d. 4.3 g of SrBr2 x 1 mol SrBr2 / 247.42 g SrBr2 = 0.0174 mol SrBr2 e. 2.5 g of NaOH x 1 mol NaOH / 40 g NaOH = 0.625 mol NaOH f. 1.87 g of Ca(OH)2 x 1 mol Ca(OH)2 / 74.1 g Ca(OH)2 = 0.025 mol Ca(OH)2 5. Convert the following to moles (and millimoles). a. 1.68 g of Ba(OH)2 x 1 mol Ba(OH)2 / 171.34 g Ba(OH)2 = 0.0098 mol (9.8 mmol) Ba(OH)2 b. 0.792 g of H3PO4 x 1 mol H3PO4 / 98 g H3PO4 = 0.008 mol (8.1mmol) H3PO4 c. 3.21 g of K2S x 1 mol K2S / 110.27 g K2S = 0.0291 mol K2S (29.1 mmol) K2S d. 0.8692 g of Cu(NO3)2 x 1 mol Cu(NO3)2 / 187.57 g Cu(NO3)2 = 0.00463 mol (4.63 mmol) Cu(NO3)2 e. 10.648 g of Ba3(PO4)2 x 1 mol Ba3(PO4)2 / 601.9 g Ba3(PO4)2 = 0.0177 mol (17.7 mmol) Ba3(PO4)2 f. 5.79 g of (NH4)2SO4 x 1 mol (NH4)2SO4 / 132.17 g (NH4)2SO4 = 0.044 mol (44 mmol) (NH4)2SO4 g. 1.32 g of Pb(C2H3O2)2 x 1 mol Pb(C2H3O2)2 / 325.3 g Pb(C2H3O2)2 = 0.0041 mol (4.1 mmol) Pb(C2H3O2)2 h. 4.29 g of CaCl2 ∙6H2O x 1 mol CaCl2 ∙6H2O / 219.1 g CaCl2 ∙6H2O = 0.0196 mol (19.6 mmol) CaCl2 ∙6H2O 6. Convert the following to moles (and millimoles). a. 0.089 g of silver nitrate (AgNO3) x 1 mol AgNO3/ 169.88 g AgNO3 = 5.24E-4 mol (5.24E-1 mmol) AgNO3 b. 1.62 g of aluminum chloride (AlCl3) x 1 mol AlCl3/ 133.33 g AlCl3 = 0.0122 mol (12.2 mmol) AlCl3 c. 2.37 g of calcium carbonate (CaCO3) x 1 mol CaCO3/ 100.09 g CaCO3 = 0.0237 mol (23.7 mmol) CaCO3 d. 1.004 g of iron(II) sulfide (FeS) x 1 mol FeS/ 87.92 g FeS = 0.0114 mol (11.4 mmol) FeS e. 2.12 g of dinitrogen pentoxide (N2O5) x 1 mol N2O5/ 108.02 g N2O5 = 0.0197 mol (19.7 mmol) N2O5 f. 2.68 g of lead(II) nitrate (Pb(NO3)2) x 1 mol Pb(NO3)2/ 331.22 g Pb(NO3)2 = 0.0081 mol (8.1 mmol) Pb(NO3)2 g. 3.02 g of ammonium phosphate ((NH₄)₃PO₄) x 1 mol (NH₄)₃PO₄/ 149.12g (NH₄)₃PO₄ = 0.0203 mol (NH₄)₃PO₄ h. 5.852 g of sulfuric acid (H2SO4) x 1 mol H2SO4/ 98.09 g H2SO4 = 0.0597 mol (59.7 mmol) H2SO4 i. 4.735 g of potassium dichromate (K2Cr2O7) x 1 mol K2Cr2O7/294.2 g K2Cr2O7 = 0.0161 mol (16 mmol) K2Cr2O7 7. What is the mass of each substance in grams (and milligrams)? a. 5.68 mol of Ag x 107.87 g Ag/ 1 mol Ag = 613 g (6.13E+5 mg) Ag b. 2.49 mol of Sn x 118.71 g Sn/ 1 mol Sn = 295.6 g (2.96E+5 mg) Sn c. 0.0873 mol of Os x 190.2 g Os/ 1 mol Os = 16.6 g (1.7E+4 mg) Os d. 1.74 mol of Si x 28.09 g Si/ 1 mol Si = 48.88 g (4.9E+4 mg) Si e. 0.379 mol of H2 x 2.02g H2/ 1 mol H2 = 0.766 g (7.7E+2 mg) H2 f. 1.009 mol of Zr x 91.22g Zr/ 1 mol Zr = 92.04 g (9.2E+4 mg) Zr 8. What is the mass of each substance in grams (and milligrams)? a. 2.080 mol of CH3OH x 32.05 g CH3OH/ 1 mol CH3OH = 66.66 g (6.7E+4 mg) CH3OH b. 0.288 mol of P4 x 123.88 g P4 / 1 mol P4 = 35.677 g (3.6E+4 mg) P4 c. 3.89 mol of ZnCl2 x 136.29g ZnCl2 / 1 mol ZnCl2 = 530.17 g (5.3E+5 mg) ZnCl2 d. 1.800 mol of Fe(CO)5 x 195.9g Fe(CO)5 / 1 mol Fe(CO)5 = 352.62 g (3.5E+5 mg) Fe(CO)5 e. 0.798 mol of S8 x 256.56g S8 / 1 mol S8 = 204.7 g (2.0E+5 mg) S8 f. 4.01 mol of NaOH x 40g NaOH/ 1 mol NaOH = 160.4g (1.6E+5 mg) NaOH 9. What is the mass of each compound in kilograms? a. 6.38 mol of P4O10 x 283.88g P4O10/ 1 mol P4O10 = 1811.15g x 1 kg/ 1000 g = 1.8 kg P4O10 b. 2.26 mol of Ba(OH)2 x 171.34g Ba(OH)2/ 1 mol Ba(OH)2 = 387.23 g x 1 kg/ 1000 g = 0.39 kg Ba(OH)2