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O. Givan the following data, calculste the nomal boiling point for fomic acid HC

ID: 1008499 • Letter: O

Question

O. Givan the following data, calculste the nomal boiling point for fomic acid HCOOH). 410 363 130.0 250.9 HCOOHg) a) 0.39 *C b) 389*0 c) 662 C d) 279 -C e 116 °C 1 1 . For which of the following processes would ASbe expected to be most positive? 12. Which of the following statamants is (are) always true? L In order for a process to be spontaneous, the entropyofthe universe must ncrease IL A system cannothave both energy disorder and positional disorder LIL IV. Sis zero for elements in their standard states a) I unix = 13. For the reaction CLOg)-yo,( )2coAs), AF-126.4 kDmol and AS--74.9 JK mol At 373°C, what is 4 a) 154.3 kJmol b) 48.5Imol c 174.81 mol d) 78.0kImol e 156.6kImol

Explanation / Answer

10. Answer is e. 116oC

Boiling: HCOOH(l) --> HCOOH(g)

H of boiling:
H of product - reactant = -363 kJ - ( -410 kJ) = 47kJ

S of boiling:
S of product - reactant = 250.9 J/K - (130 J/K) = 120.9 J/K

the formula:
G = H - TS

when at equilibrium ( melting or boiling points), becomes:
zero = H - TS

this rearranges to:
T = H / S

T = 47,000 joules / 120.9 joules

T = 388.75 Kelvin

388.75 Kelvin - 273 = 115.75o Celsius = 116oC = T = Normal Boiling Point of Formic Acid

11. Answer is d. 2NH4NO2(s) -------> 2N2(g) + O2(g) + 4H2O(g)

12. Answer is a. I

13. Answer is d. 78.0 kJ/mol

G = H - TS = 126.4kJ/mol - (646K)(0.0749kJ/Kmol) = 78.0kJ/mol

14. Answer is d. 2.72 * 1042

G = Gf(Product - reactant) = -32.88-209.2 = -242.08 kJ/mol

Keq = e-G/RT = e-((-242.08)/0.008314 * 298) = 2.72 * 1042

15.Answer is d. -9.90kJ

G = -RTlnKeq = -0.008314 * 700 * ln (5.48) = -9.90 kJ