Download Final Exam Problems - General Chemistry I | CHM 1045 and more Exams Chemistry in PDF only on Docsity! CHM1045 Name: FINAL EXAM Section: h = 6.6310-34 J sec c = 3.00108 m/sec R = 0.0821 l atm/mol K = 8.31 kg m2/s2 mol K (ideal gas constant) R = 2.1810-18 J 1 nm = 10-9 m; 1 Å = 10-10 m; 1 atm = 760 torr Professor Stiegman’s shoe size; 9.5 1.) (5) What is the molecular weight of glucose, C6H12O6 2.)(5) Calculate the number of oxygen atoms in 25.0 g of CaCO3. 3.)(15) Determine the percent composition (by weight) of each element in Mg3(PO4)2 4.)(5) What is the molarity of an NaOH solution which contains 24.0 g of NaOH dissolved in 200 mL of solution? 5.)(15) Using the van der Waals equation calculate the pressure exerted by 10.0 moles of CO2 in a 2.00 L vessel at 47 °C? (a = 3.59 L2 atm/mol2; b = 0.0427 L/moles) The van der Waals equation corrects for non-ideal behavior of a gas, what specifically do the coefficients a and b correct for? 6.)(20) For the combustion of sucrose,C12H22O11, shown below. a.) How many moles of oxygen are required to react with 1.00 g of sucrose? C12H22O11 + 12O2 12CO2 + 11H2O 8.) (20) Given the precipitation of AgCl from a NaCl solution using silver nitrate: AgNO3 + NaCl(aq) AgCl(s) + NaNO3(aq) If a solution of AgNO3 of unknown molarity is added to a flask containing 132 ml of NaCl solution also of unknown molarity. At the endpoint 42.15 ml of the AgNO3 solution have been added and 8.42 g of AgCl are recovered as a precipitate from the reaction: a.) What is the molarity of the NaCl solution? b.) What is the molarity of the AgNO3 solution? 9.) (20) The thermochemical reaction for the combustion of 1 mole of methane is given below. From the enthalpy and the bond dissociation enthalpies given below determine the bond dissociation enthalpy of the C=O in CO2. CH4(g) + 2O2(g) CO2(g) + 2H2O(g) DH = -669.68 kJ mol-1 DH(C-H) = 418.0 kJ/mol ; DH(O2) = 498.7 kJ/mol ; DH(H-O) = 464.0 kJ/mol. 10.)(15) Write the electron configurations for the following ions or elements: example: Mg [Ne](3s)2 a.) Si b.) Ir3+ c.) Se 11.) (20 pts) A laser irradiates 1.5 grams of aluminum at a wavelength of 488 nm. At the end of the irradiation the aluminum is 3 degrees warmer. How many moles of photons were absorbed? (Specific heat Al, Cp = 0.900 J/g ·K; h=6.63x10-34J·s; c=3.00x108m/sec) (*Be careful of units!) 12.)(20) What is the enthalpy change associated with heating 20 g of Al is from room temperature (23 °C) to its melting point at 660 °C and then melting it. (Specific heat of Al, Cp = 0.900 J/K g; DHfus = 437.5 kJ/mole)
