Quiz 2A with Answer Key - General Chemistry | CHEM 1120 | Quizzes Chemistry

CHEM1120-001 Quiz 2A Chapters 15&16 - Thermo & Kinetics Spring 2006 Northrup

26. Given the following at 25°C and 1.00 atm:

1/2N2(g) + O2(g) → NO2(g)

ΔH0 = 33.2 kJ

N2(g) + 2O2(g) → N2O4(g)

ΔH0 =11.1 kJ

Calculate the ΔH0 for the following reaction at 25°C: 2NO2(g) → N2O4(g)

-55.3 kJ

-22.1 kJ

+11.0 kJ

+55.3 kJ

+44.3 kJ

27. If 4.20 kJ of heat is added to a calorimeter containing 75.00 mL of water, the temperature of the water and the

calorimeter increases from 24.6°C to 35.8°C. In the same calorimeter, a 50.0 mL solution of 1.2 M HCl at

24.1°C is mixed with 50.0 mL of 1.2 M NaOH, also at 24.1°C. After the reaction occurs, the temperature of the

resulting mixture is 29.8°C. Calculate the molar heat of neutralization. Assume the specific heat of the solution

is the same as pure water, 4.184 J/g•°C.

-33.9 kJ/mol

-41.7 kJ/mol

-45.6 kJ/mol

-13.0 kJ/mol

-58.5 kJ/mol

28. Which of the following is not a formation reaction?

H2(g) + 1/2O2(g) → H2O(l)

4Al(s) + 3/2O2(g) → Al2O3(s)

1/2H2(g) + 1/2 Br2(l) → HBr(g)

Ca(s) + 1/2O2(g) → CaO(s)

H2O(l) + SO3(l) → H2SO4(l)

29. Given the standard heats of formation for the following compounds (listed below each compound in kJ/mol),

calculate ΔH for the following reaction.

CH4(g)

+ H2O(g)

→

CH3OH(l)

+ H2(g)

-75

-242

-238

+555kJ/mol

-79 kJ/mol

+79 kJ/mol

-555 kJ/mol

- 405kJ/mol

30. For the following reaction at 25°C, ΔH0 = -26.88 kJ/mol and ΔS0 = 11.2 J/mol-K. Calculate ΔG0 for the reaction:

I2(g) + Cl2(g) → 2ICl(g) at 25°C in kJ/mol.

+77.0 kJ/mol

-102 kJ/mol

+50.6 kJ/mol

-30.2 kJ/mol

31. For the reaction SiH4(g) + 2O2(g) → SiO2(s) + 2H2O(l), ΔH0 = -1516 kJ/mol at 25°C and ΔS0 = - 432.8 J/mol-K

at 25°C. This reaction is spontaneous __________.

only above a certain temperature

cannot tell from the info available

at no temperatures

at all temperatures

only below a certain temperature

32. Estimate the temperature at which ΔG = 0 for the reaction NH3(g) + HCl(g) → NH4Cl(s), having a ΔH = -176

kJ/mol and a ΔS = -284.5 J/mol-K.

619 K

634 K

467 K

582 K

680 K

33. Which one of the following reactions has a positive entropy change?

N2(g) + 3H2(g) → 2NH3(g) d) BF3(g) + NH3(g) → F3BNH3(s)

H2O(g) → H2O(l) e) 2NH4 NO3(s) → 2N2(g) + 4H2O(g) + O2(g)

2SO2(g) + O2(g) → 2SO3(g)

34. The decomposition of dinitrogen pentoxide obeys the rate-law expression Rate = k[N2O5] where k=0.080 min-1.

If the initial concentration of N2O5 is 0.30 M, what is the concentration after 2.6 minutes? N2O5 → N2O3 + O2

0.38 M

0.028 M

0.32 M

0.13 M

0.24 M

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CHEM1120-001 Quiz 2A Chapters 15&16 - Thermo & Kinetics Spring 2006 Northrup

Given the following at 25°C and 1.00 atm: 1/2N 2 (g) + O 2 (g) → NO 2 (g) Δ H^0 = 33.2 kJ N 2 (g) + 2O 2 (g) → N 2 O 4 (g) Δ H^0 =11.1 kJ Calculate the Δ H^0 for the following reaction at 25°C: 2NO 2 (g) → N 2 O 4 (g) a) -55.3 kJ b) -22.1 kJ c) +11.0 kJ d) +55.3 kJ e) +44.3 kJ
If 4.20 kJ of heat is added to a calorimeter containing 75.00 mL of water, the temperature of the water and the calorimeter increases from 24.6°C to 35.8°C. In the same calorimeter, a 50.0 mL solution of 1.2 M HCl at 24.1°C is mixed with 50.0 mL of 1.2 M NaOH, also at 24.1°C. After the reaction occurs, the temperature of the resulting mixture is 29.8°C. Calculate the molar heat of neutralization. Assume the specific heat of the solution is the same as pure water, 4.184 J/g•°C. a) -33.9 kJ/mol c) -41.7 kJ/mol e) -45.6 kJ/mol b) -13.0 kJ/mol d) -58.5 kJ/mol
Which of the following is not a formation reaction? a) H 2 (g) + 1/2O 2 (g) → H 2 O( l ) d) 4Al(s) + 3/2O 2 (g) → Al 2 O 3 (s) b) 1/2H 2 (g) + 1/2 Br 2 ( l ) → HBr(g) e) Ca(s) + 1/2O 2 (g) → CaO(s) c) H 2 O( l ) + SO 3 ( l ) → H 2 SO 4 ( l )
Given the standard heats of formation for the following compounds (listed below each compound in kJ/mol), calculate Δ H for the following reaction. CH 4 (g) + H 2 O(g) →^ CH 3 OH(l) + H 2 (g) -75 -242 -238 0 a) +555kJ/mol b) -79 kJ/mol c) +79 kJ/mol d) -555 kJ/mol e) - 405kJ/mol
For the following reaction at 25 °C, Δ H^0 = -26.88 kJ/mol and Δ S^0 = 11.2 J/mol-K. Calculate Δ G^0 for the reaction: I 2 (g) + Cl 2 (g) → 2ICl(g) at 25°C in kJ/mol. a) +77.0 kJ/mol b) -102 kJ/mol c) +50.6 kJ/mol d) -30.2 kJ/mol
For the reaction SiH 4 (g) + 2O 2 (g) → SiO 2 (s) + 2H 2 O(l), Δ H^0 = -1516 kJ/mol at 25 °C and Δ S^0 = - 432.8 J/mol-K at 25°C. This reaction is spontaneous __________. a) only above a certain temperature d) cannot tell from the info available b) at no temperatures e) at all temperatures c) only below a certain temperature
Estimate the temperature at which Δ G = 0 for the reaction NH 3 (g) + HCl(g) → NH 4 Cl(s), having a Δ H = - kJ/mol and a Δ S = -284.5 J/mol-K. a) 619 K b) 634 K c) 467 K d) 582 K e) 680 K
Which one of the following reactions has a positive entropy change? a) N 2 (g) + 3H 2 (g) → 2NH 3 (g) d) BF 3 (g) + NH 3 (g) → F 3 BNH 3 (s) b) H 2 O(g) → H 2 O(l) e) 2NH 4 NO 3 (s) → 2N 2 (g) + 4H 2 O(g) + O 2 (g) c) 2SO 2 (g) + O 2 (g) → 2SO 3 (g)
The decomposition of dinitrogen pentoxide obeys the rate-law expression Rate = k[N 2 O 5 ] where k=0.080 min-1. If the initial concentration of N 2 O 5 is 0.30 M , what is the concentration after 2.6 minutes? N 2 O 5 → N 2 O 3 + O 2 a) 0.38 M b) 0.028 M c) 0.32 M d) 0.13 M e) 0.24 M

Calculate the activation energy of a reaction if the rate constant is 0.75 s-1^ at 25°C and 11.5 s-1^ at 75°C. a) 681 J/mol b) 47.1 kJ/mol c) 15.8 kJ/mol d) 20.4 kJ/mol e) 31.4 kJ/mol
The gas phase reaction SO 2 Cl 2 → SO 2 + Cl 2 obeys the rate-law expression rate = k [SO 2 Cl 2 ]. At 593 K the rate constant is 2.2 × 10 -5^ s-1. A 2.0-g sample of SO 2 Cl 2 is introduced into a closed 4.0-L container. How much time must pass in order to reduce the amount of SO 2 Cl 2 present to 1.8 grams? a) 3.5 × 102 s b) 2.1 × 102 s c) 7.4 × 103 s d) 4.8 × 103 s e) 5.8 × 104 s
The gas-phase reaction 2NO + 2H 2 → N 2 + 2H 2 O has the following rate law expression, rate = k[NO]^2 [H 2 ]. If the [NO] is halved and the [H 2 ] is tripled, what change in rate is expected? a) Change by factor 9/4 b) Change by factor 4/3 c) Change by factor 3/4 d) Change by factor 3/
In the reaction N 2 + 3H 2 → 2NH 3 the rate of formation of NH 3 is 0.15 M-1•min. What is the rate of loss of H 2? a) 0.20 M-1•min b) 0.15 M-1•min c) 0.075 M-1•min d) 0.225 M-1•min
Given the following data for the NH 4 +^ + NO 2 -^ → N 2 + 2H 2 O reaction Trial [NH 4 +] [NO 2 - ] Rate 1 0.010 M 0.020 M 0.020 M /s 2 0.015 0.020 0. 3 0.010 0.010 0. The rate law for the reaction is: a) rate = k [NH 4 +][NO 2 - ]^2 c) rate = k [NH 4 +]^2 [NO 2 - ] e) None of the above b) rate = k [NH 4 +]^2 [NO 2 - ]^2 d) rate = k [NH 4 +][NO 2 - ]
At 300 K the reaction 2NOCl → 2NO + Cl 2 obeys the rate law rate = k [NOCl]^2 where k = 2.8 × 10 -5^ M -1•s-1. Suppose 1.0 mole of NOCl is introduced into a 2.0-liter container at 300 K. How much NOCl will remain after 1,800 seconds? a) 0.87 mol b) 0.97 mol c) 0.84 mol d) 0.77 mol e) 0.63 mol
Consider the hypothetical reaction A + 2B → AB 2. Assume that the following proposed mechanism is consistent with the rate data. B + B → B 2 slow B 2 + A → AB + B fast B + AB → AB 2 fast Which one of the following statements must be true? The reaction is __________. a) second order in A and second order overall b) first order in A, second order in B, and third order overall c) second order in B, zero order in A, and third order overall d) second order in B and second order overall e) first order in A and first order overall
In the hypothetical reaction of question #41, a) B 2 and AB are intermediates and A is a catalyst. b) B 2 is the only intermediate and A is a catalyst. c) B 2 and AB are intermediates and there is no catalyst. d) B 2 is the only intermediate and both A and AB are catalysts. e) B 2 is the only intermediate and there is no catalyst.
Which version of the quiz do you have? a) Version A b) Version B

Quiz 2A with Answer Key - General Chemistry | CHEM 1120, Quizzes of Chemistry

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