2008F_chem_125_exam_2_QQQQx040ri66

2008F_chem_125_exam_2_QQQQx040ri66 - Chem. 125 Exam #2 Fall...

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Chem. 125 Exam #2 Fall 2008 PART A. (4 Points each) 1. How many phosphorous atoms are in 5.0 g P 4 O 10 ? a. 4.2x10 22 b. 1.1 x10 22 c. 1.1x10 23 d. 2.6x10 21 e. 1.5x10 23 2. Which of the following is the correct name for ammonium sulfide? a. NH 4 SO 4 b. (NH 4 ) 2 SO 4 c. NH 4 SO 3 d. NH 4 S e. (NH 4 ) 2 S 3. Which of the following ionic compounds is NOT soluble in water? a. Pb(NO 3 ) 2 b. CdI 2 c. FeCO 3 d. HgCH 3 COO e. NH 4 F 4. 12.3 g sodium chloride is dissolved in enough water to make 400. mL of solution. What is the molarity of the solution? a. 0.210 M b. 0.526 M c. 0.084 M d. 1.90 M e. 0.469 M
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5. How many moles of hydrogen gas can be produced from 3.87 L of 0.30 M nitric acid when excess iron is added? The reaction is ( 29 ( 29 ( 29 ( 29 ( 29 3 3 2 3 2 6 2 3 . Fe s HNO aq Fe NO aq H g + + a. 0.29 b. 0.58 c. 1.2 d. 0.47 e. 0.23 6. Nitrogen gas is compressed adiabatically (the temperature does not change). The work done on the gas, w, is 1,500 J. What is q, the heat added to the system? a. 1,500 J b. -1,500 J c. 3,000 J d. -3,000 J e. 0 7. The specific heat of iron is 0.45 J/(g o C). How much heat is added to a 15.09 g iron nail to raise its temperature from 150 o C to 450 o C? a. 4.1 kJ b. 10. kJ c. 1.0 kJ d. 2.0 kJ e. 3.1 kJ 8. 500. g of water is in a Styrofoam calorimeter of negligible heat capacity. The initial T of the water is 23.5 o C. After 368.4 g of an unknown alloy at 100. o C is added, the equilibrium T is 30.3 o C. What is the specific heat of the unknown compound in J/(g o C)? The specific heat of water is 4.184 . J
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2008F_chem_125_exam_2_QQQQx040ri66 - Chem. 125 Exam #2 Fall...

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