28. Which of the following binary compounds has two different solid-state structures?
(A) NaCl
(B) CsCI
(C) CaF₂
(D) NiAs
(E) ZnS

24. Cisplatin is a well-known anticancer drug with the chemical formula Pt(NH3)2CI2. Which of the following statements is true? (A) Both Raman and IR spectra of cisplatin show two bands in the Pt-CI stretching region. (B) Only the Raman spectrum of cisplatin shows two bands in the Pt-CI stretching region； the IR spectrum does not show any bands in the Pt-Cl stretching region. (C) Only the infrared spectrum of cisplatin shows two bands in the Pt-CI stretching region； the Raman spectrum does not show any bands in the Pt-Cl stretching region. (D) Both Raman and IR spectra of cisplatin do not show any bands in the Pt-CI stretching region. (E) None of the above.

25. Which of the following is a measure of the randomness of a system in thermodynamics? (A) Energy (B) Pressure (C) Heat transfer (D) Work done(E) Entropy

26. What is the relationship between the activation energy and rate constant of a chemical reaction? (A) The rate constant is proportional to the negative activation energy. (B) The rate constant is inversely proportional to the negative activation energy. (C) As the activation energy decreases, the rate constant remains constant. (D) As the activation energy increases, the rate constant increases exponentially. (E) As the activation energy increases, the rate constant decreases exponentially.

27. Organic compounds can be classified based on their functional groups. Which of the following is not a functional group? (A) Isocyano (B) CarbonyI (C) Isocyanide (D) Carboxyl (E) None of the above

29. Which of the following compounds is typically not needed for the conversion of trialkyI borane to an alcohol? (A) Sodium hydroxide (B) Water (C) Diborane (D) Hydrogen peroxide (E) None of the above

30. Arrangement of nucleotides in DNA can be seen using which of the following methods? (A) Electron microscopy (B) Electrospray ionization mass spectrometry (C) X-Ray crystallography (D) Cyclic voltammetry (E) Fourier-transform infrared spectroscopy

31. A ball at rest with mass m and radius r Ci.e. rotational inertia I= ) rolls without sliding from a bowl of radius R from height h (see figure below). The coefficient of static friction between the ball and the bowl is μ. What is the maximum height it can reach on the other side of the bowl? (A)(B) (C)h (D)(E)μh

32. A cannonball of mass 10.0 kg is fired upward. The cannonball explodes into 3 pieces when it reaches the maximum height. At the moment of explosion, a 5-kg piece carries velocitywhile another 4-kg piece carries velocity. What is the velocity of the third piece? (A) Cannot be determined without knowing the energy provided by the explosion (B)(C)(D)(E)

33. Two bodies of mass m are connected individually to strings of length R, which are both pinned at P, as shown in the right figure. One body is raised with an angle θ and then released to swing. When the bodies collide, they stick to each other. Find the frequency of the motion after the collision.(A)(B)(C)(D)(E)

34. A block of density 800 kg/m3 floats face down in a fluid of density 1200 kg/m3. The block has height H= 6 cm. If the block is held fully submerged and then released, what is the magnitude of its initial acceleration? (A) 2.45 m/s2 (B)19.6 m/s2(C)0m/s2 (D)9.8 m/s2 (E) 4.9 m/s2