58. The following equation shows the decay process of uranium-238 through the emission of an a-particle: . Which of the following is the element X?
(A)
(B)
(C)
(D)
(E)

54. A patient's prosthetic leg, weighing 5 kg, is sliding across the floor with a coefficient of kinetic friction of 0.2. What is the force of friction acting against the leg? (g = 9.8m/s²) (A) 9.8 N (B) 1N (C) 49 N (D) 1.96 N (E) 245 N

55. How long will it take for an oscillator at a frequncy of 2.5 Hz to make 100 vibrations? (A) 250 s (B) 40 s (C) 25 s (D) 4 s (E) 0.025 s

56. Cobalt Co Co has a half-life of 5 years. If there was sample of that isotope with an initial mass of 240 g, how much of the sample remains after 30 years? (A) 30 g (B) 15 g (C) 7.5 g (D) 3.75 g (E) 0.89 g

57. Unpolarized light of the intensity I0 passes through two polaroids. The axis of the first polaroid is vertical. The second polariod is at 30° to the vertical. Find the intensity of the transmitted light. (A) (3/4)I0 (B) (3/8)I0 (C) (1/4)10 (D) (1/8)I0 (E) (1/2)I0

59. Suppose a healthy bone can withstand compressive stress of 181 N/mm² before breaking. If the cross-sectional area of the bone is 3.2 cm², how much weight (in kg) can it support? (gravitational acceleration g = 9.8m/s²) (A) 2790 kg (B) 3240 kg (C) 5910 kg (D) 2072 kg (E) 4790 kg

60. The light intensity incident on a metallic surface produces photoelectrons with a maximum kinetic energy of 2 eV. The light intensity is doubled. Determine the maximum kinetic energy of the photoelectrons (in eV). (A) 4 eV (B) 2 eV (C) √2 eV (D) 1 eV (E) 8 eV

61. Arrange the steps below in the order required to perform a Kjeldahl Nitrogen Analysis. I Distillation of ammonia into standard hydrochloric acid. II Neutralize ammonium to release ammonia.  III Digest the organic sample with boiling sulfuric acid to convert nitrogen to ammonium. IV Titrate unreacted standard hydrochloric acid with sodium hydroxide. (A) III, II, I, IV (B) II, I, IV, III (C) I, IV, III, II (D) IV, III, II, I (E) III, I, IV, II

62. What is the product of the following reaction? (A)(B)(C)(D)(E)

63. Stray light is a problem for spectrophotometers that are not tightly sealed. What is the main impact of stray light on the recorded absorbance? (A) The apparent absorbance is greater than the true absorbance and increases as the amount of stray light increases. (B) The apparent absorbance is greater than the true absorbance and decreases as the amount of stray light increases. (C) The apparent absorbance is less than the true absorbance and increases as the amount of stray light decreases. (D) The apparent absorbance is less than the true absorbance and decreases as the amount of stray light decreases. (E) It is impossible to determine effect of stray light on measured absorbance.

64. How many unpaired electrons are there in an atom of oxygen in its ground state? (A) 1 (B) 2 (C) 4 (D) 0 (E) 3