24. Phosphorus-32 (P-32) is a commonly used radioactive nuclide in biochemical research, particularly in studies of nucleic acids. The half-life of P-32 is 14.3 days. What mass of P-32 is left from an original sample of 175 mg of Na₃ ³²PO₄ after 35.0 days? Assume the atomic mass of 32-P is 32.0.
(A)6.22 mg
(B)62.20 mg
(C)0.12 mg
(D) 1.24 mg
(E)12.44 mg

20. What is the  for H2O(g) + (1/2)O2(g) ←→ H2O2(g) at 600. K using the following data: H2(g) + O2(g) ←→ H2O2(g) K = 2.3 × 106 at 600. K 2H2(g) + O2(g) ←→ 2H2O(g) K = 1.8 × 1037 at 600. K? (A)-7.1 × 104 J/mol(B)1.4 × 105 J/mol(C)1.1 × 105 J/mol (D) 7.9 × 103 J/mol (E)1.0 × 103 J/mol

21. Which of the following statements is correct? (A)For 2H2(g) + O2(g) → 2H2O(l), its  is larger than 0 (> 0)(B)The So of C2H5OH(l) is larger than the So of C2H5OH(g) (C)One mol N2 (at STP) has more positional probability than 1 mol N2 at 100 K, 2.0 atm. (D) The sign of  for the process of H2O(l) → H2O(g) is positive (+). (E)At constant T and P, the change with  is not a spontaneous process.

22. An electrochemical cell consists of a standard hydrogen electrode and a copper metal electrode. What is the potential of the cell at 25℃ if the copper electrode is placed in a solution in which [Cu2+] = 2.5 × 10-4 M. [Note: Cu2+(aq) + 2e- → Cu(s), E0 = 0.34 V] (A)0.23 V(B)-0.16 V(C)0.018 V (D) 0.26 V (E)0.059 V

23. Which of the following compound is not going to dissolve in carbon tetrachloride? (A)CO2(B)CH2=CH2(C)NH4NO3 (D) KrF2 (E)C6H14 (Hexane)

25. Which of the following statements is correct? (A)The low-spin Ru(NH3)6 2+ ion has 4 unpaired electrons.(B)The Ni(H2O)6 2+ ion has 0 unpaired electrons. (C)The diamagnetic PdCl4 2- ion has a tetrahedral d8 structure. (D) CN- is a weaker field ligand than SCN-1 because the Fe(CN)6 3- ion is paramagnetic with one unpaired electron and the Fe(SCN)6 3- ion has five unpaired electrons. (E)The F- ligand in the CrF6 4- ion produces a weak field because the ion is known to have four unpaired electrons.

Part I. Vocabulary: Choose the answer that best completes the sentence. 30% 1. Because the girl was crippled, she was _____ to a wheelchair. She had so much difficulty going outdoors. (A) confined (B) condensed (C) conducted (D) consisted

2. Head delegations from the countries are now at the negotiation tables in the first round of _____ talks, the results of which are hoped to be the beginning of improved relations between the two nations. (A) bicameral (B) bifocal (C) binomial (D) bilateral

3. She always had to _____ to her father’s wishes, whether or not she agreed with him. He wishes that she would be back home no later than 8 o’clock in the evening. (A) claim (B) relieve (C) elicit (D) defer

4. James Brooks is considered by many around him to be a(n) _____. They don’t expect him to help others. (A) philanthropist (B) activist (C) egoist (D) humanitarian

5. Some drugs are known to create an _____ bodily condition for those who use them. (A) indulgent (B) insensate (C) inalienable (D) intentional