Question

rele the best answer and mark on the Scantron card.- Four points each. 100 ponts 1) Determine the percent yield of a reaction that produces 28.65 g of Fe when 50.00 g of Fez03 react 1) with excess Al according to the following reaction. FezO3(s)+2 Al(s) - Al2O3(s)+2 Fe(s) A) 81.93 % B) 57.30 % C) 20.02 % D) 28.65 % E) 61.03 % 2) Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according to the chemical equation shown below. When 0.030 mol of Na is added to 100.00 g of water, the temperature of the resulting solution rises from 25.00 C to 37.90°C. If the specific heat of the solution is 4.18 J/(g "C ) , calculate AH for the reaction, as written 2 Na(s)+2 H20D-2 NaOH(aq)+ H2(g) A)-5.41 k 2) B AH- C)-90.0 k B) 4360 k D)-180 k A Using the following equation for the combustion of octane, calculate the heat of reaction for 100.0g of octane. The molar mass of octane is 114.33 g/mole. 3) 2 C8H18 25 O2-16 CO2+ 18 H20 AHnn-11018 k A) 4.82 x 103 k 9.64 x 103 k D) 1.26 x 104 kJ B) 4.82 k 4) It takes 11.2 kJof energy to raise the temperature of 145 g of benzene from 25.0°C to 70.0°C. What is the specific heat of benzene? A) 5.41 Jg C) 4) D) 1.10 1/(g C c) 1.72 1(g "C) B) 3.48 1/(g C) 5) C 5) Estimate AG°nxn for the following reaction at 449.0 K AH-94.9 kJ; AS--224.2 J/K CH2O(g)+2 H2(g)- CH4(g) + H20(g) C+5.8 kJ D)-101 k E)-4.2 k B) +2.4 k A) +12.9k 6) Which of the following processes is endothermic? A) the combustion of propane B) the chemical reaction in a "hot pack" often used to treat sore muscles 9 the freezing of water Dthe vaporization of rubbing alcohol E) a hot cup of coffee (system) cools on a countertop 6) 7) Using the following thermochemical equation, determine the amount of heat produced from the combustion of 24.3 g benzene (C6H6). The molar mass of benzene is 78.11 g/mole. 7) AHxn-6278 k] 2 C6H6)+15 O2(8) 12 CO2(g)+6 H2O(g) A) 3910 k E) 977 kJ B) 0.302 kJ 1950 kJ D) 40.1 k B-1

Answer 1

I I o Fq O3 + 2 Al Al2 O3 at 2Fe: so, moles of Feroz: mass mass... 350.0 30.313 mol 159.7 gimol . . .' By snn, Imol Fezös produce a more... 70.313 mol Fe2O3 prodyle= (2x0.313)mol Fe . = 0.626 mol Fe Now, mass= moles x molar mass of Fe = 0.626 mol X 55.845.glmol = 34.969 now, % yields actual yield x1000) theoretical yield = 26.658x100% 81.937) 1 34.969