Ceneral Chemistry Second Exam 2019

Time: 60 min. Student's Name:.......... Section No. Physical constants and useful relations: General Chem. Second Exam 1 atm101.3 kPa 1.013 x 10 Pa-760. Torr , Planck's constant 6.63x10 J.5, Speed of light-3.00 x10 m/s; R-0,08206 1. atm/mol. K-8.314J/mol.K Αν. Νο. - 6.022 x 10 mol. E-(2.18 x10%/n²) J; E= he/ 11. atm 101.3 J; =h/mu PV=nRT . [P+a(n/V)²] (V-nb)=nRT 14ms(3RT/M); AE-q+w, ΔΗ ΔΕ + Ρ Χ AV, wPxAV ANSWER SHEET 1. a b C e 9. a b cd 2. a bd e 10. a b Xd e 3. a C d e 11. a C b d C d e 12. a b C d 5. a bd e 13. a e 6. a d e b 14. Xb C d e 7. a C cofe 15. a e 8. a b C e 16. a bd e 1. Which of the following statements concerning gases is correct? a) All gases behave ideally at high P and/or low T. No gases behave ideally at low P and/or high T. c) No gases behave ideally at high P and/or high T. All gases behave ideally at low P and/or high T real TN Idesd Tohigh xe) Both van der Waals constants (a & b) are the same for all gases Thigh 2. Which of the following statements concerning ideal gases is incorrect (not correct)? a) At constant n and T, PVP2 V2. b) The average molecular speed is higher for H₂ gas than for N, gas at same T. The average kinetic energy is higher for H, gas than for N, gas at same T. d) At constant n, PV1/T1-P2V2 T2. c) At constant n and V. P/TP2/T2. 3. According to Kinetic Molecular Theory of gases, the root-mean square speed (uma) of N₂ gas (M= 28.0 g/mol) at 25°C is equal to a) 411 m/s 515 m/s c) 610. m/s d) 682 m/s e) 742 m/s 3RT M 3+298 2810-3 4. Given that the density for an ideal gas (d-1.801 g/L) at 1.00 atm and 25°C, the molar mass (M in g/mol) of the gas is equal to a) 44.0 g/mol b) 30.0 g/mol c) 610. g/mol d) 58.0 g/mol e) 72.0 g/mol MORT M= JRT P M=1,801020298 5. The nitrogen (N2) gas obtained from the decopmposition of sodium azide (NaNa) according to the chemical reaction: 2 NaN) → 2 Na(s) + 3 N200 was collected over liquid trm water at a total pressure of 724 torr and 25°C where the vapor pressure of water was 24.0 torr. If the volume of the Ni gas was 10.0 1., then the mass of N₂ gas is equal to.... (Molar mass of N₂ 28.0 g/mole) a) 5.27 g b) 15.8. g PART 10.5 g 31 PVM RT d) 21.1 g 2952-0,03 021 e) 38.7 g PART V 10 35928-0087248 25 002-298 3 M 7 125 1,375 P=nRT 298 0.082 43 25 6. Given that 4.00 g of CH. gas (M16.0 g/mol) and 22.0 g of C3Hs gas (M44.0 g/mol) were placed in a 25.0 L container at 25°C, then the total pressure (P in kPa) of the gas mixture would be equal to = Fam V 75-0.08-249 a) 92.9 kPa b) 61.9 kPa 74.3 kPa 25 d) 53.1 kPa e) 40.8 kPa + The combustion (oxidation) of propane (M44.0 g/mole) is described by the balanced equation Calaculate the mass of propane (in gram) must be burned to produce 175.5 kJ of heat. CH+ 502g) 3 CO2(g) 4 H2O(t) a-6.96 -13.9 c-20.9 d-3.48 e-4.40 ΔΗ-2220 kJ 12,6 2200 2220 8- Given the following data: 2C6H6 + +49 150200 AH° (kJ/mol) Calculate the standard enthalpy of combustion of benzene in (kJ/mole benzene) a)-3135.5 b) 6535.2 Prochuck reacbant (120-39351+-28452)-(2049) 9- 12CO2(g) -393.51 6H2O 285.83 c)-6270.9-3267.6 1-6535.2 6--286-12 -1714.98-422,17 -6437+ A gas is allawed to expand, at constant temperature, from a volume of 1.0 L to 10.1 L against an external pressure of 0.50 atm. If the gas absorbs 250 J of heat from the surroundings, what is the value of q, w, and AE? +250 - POU W ΔΕ 250 J -4.55 J 245 J b) -250 J -460 J -710 J c) 250 J 460 J 710 J d) -250 J 460 J 210 J 250 J -460 J -210J 10 A 100.0 ml of 0.200. M aqueous hydrochloric acid, is added to 100.0 ml of 0.200 M aqueous ammonia (NH₂) in a constant pressure calorimeter of negligible heat capacity. The initial temperature of both solutions is the same at 25.00 °C. The final temperature after mixing is 26.20 "C. Assuming the density of the solution 1.00 g/ml and its specefic heat 4.18 J/g.°C, calculate AH per mole of the reaction: 9,1-,50 460,4 250 HCI+ NH A)-58.6 kJ b)-54.3 kl-50.2kJ NH,Cla d) -42.2 kJ e) -46.0 kJ q=MSAT 7200-4.18(1.20) 1