NET, IAS, State-SET (KSET, WBSET, MPSET, etc.), GATE, CUET, Olympiads etc.: Chemistry MCQs (Practice_Test 25 of 31)
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- Which one of the following types of particles is the MOST highly penetrating to biological tissues?
- alpha particles
- beta particles
- positrons
- neutrons
- electrons
- In lecture, you observed a radioactive plate that contained uranium oxide as a pigment (i.e. … “Fiestaware” ) . What color was the plate?
- yellow
- purple
- white
- orange
- green
- An ancient wood sculpture was determined to be 2380 years old. Calculate the percentage of the carbon-14 originally present in the wood that remains today. For carbon-14: t = 5730 years.
- Americium-241 is the radioactive isotope that is used in smoke detectors. Americium-241 undergoes alpha decay with a half-life of 458 years. What is the product nuclide that is produced when americium-241 radioactively decays?
- neptunium-237
- curium-241
- plutonium-241
- americium-240
- plutonium-240
- Positron emission tomography (PET) scans are used medicinally to diagnose certain biological disorders. The most common radioactive isotope used in this procedure is fluorine-18, which is a positron emitter.In a PET scan, which one of the following species is actually measured in order to create a three-dimensional image of the afflicted organ?
- alpha particles
- beta particles
- gamma rays
- positrons
- neutrons
- In lecture, you observed a desiccator that was used for many years to store radioactive radium compounds. What color was the desiccator?
- yellow
- orange
- purple
- green
- black
- The radioactive nuclide, iodine-131, is used medicinally as a radiotracer for the diagnosis and treatment of illnesses associated with the thyroid gland. If the rate constant for decay of iodine-131 is 9.9 × 10 − 7 s − 1, calculate the half-life (in s) of iodine-131.
- Calculate the binding energy per nucleon in millions of electron volts (MeV) for nitrogen-15. The atomic mass of nitrogen-15 is 15.00011 amu.
- What is the final, stable nuclide, X, if radon-222 decays by the emission of four alpha particles and four beta particles?
- tungsten-206
- tungsten-214
- platinum-202
- platinum-210
- lead-206
- An archeologist unearths a bone sample and wants to know the age of the bone. Her chemist friend determines that 41.7% of the initial amount of carbon-14 in the bone sample has decayed. If the half-life of carbon-14 is 5730 years, the age of the bone is:
- 4460 years
- 5730 years
- 7230 years
- 10200 years
- 11460 years
- Which of the following characteristics is⟋are important considerations for radiotracers that will be used for diagnosing illness in the body?
- The radiotracer should have a short half-life.
- The radiotracer should localize in a certain part of the body.
- The radiotracer should produce radiation that can be detected externally.
- Both a and c
- All the three statements
- When a nuclide is assembled from its constituent protons, neutrons, and electrons, there is about a 1% decrease in mass. When a chemical compound is similarly made from its constituent elements there is no discernible change in mass. The best reason for this difference is that:
- chemical reactions are intrinsically different from nuclear reactions.
- the formation of a nuclide from its constituents is always exothermic whereas the formation of a compound from the elements can be either exothermic or endothermic.
- Einstein՚s equation, E = mc2, applies to nuclei but not to molecules.
- chemical reactions release far less energy than nuclear reactions and so the mass change is too small to observe.
- mass is conserved in chemical reactions but is not conserved in nuclear reactions.
- The mass of chlorine-37 is 36.96590 amu. The binding energy per nucleon of chlorine-37 is:
- -1.41 × 10 − 12 J⟋nucleon
- 1.29 × 10 − 12 J⟋nucleon
- 1.37 × 10 − 12 J⟋nucleon
- 5.08 × 10 − 11 J⟋nucleon
- 5.08 × 10 − 8 J⟋nucleon
- The only stable nuclide with A = 35 is chlorine-35. Which of the following equations correctly describe the process by which phosphorus-35 decays to chlorine-35?
- phosphorus-35 ⇾ chlorine-35 + beta particle
- phosphorus-35 ⇾ sulfur-35 + beta particle sulfur-35 ⇾ chlorine-35 + beta particle
- phosphorus-35 ⇾ silicon-35 + beta particle silicon-35 ⇾ chlorine-35 + beta particle
- phosphorus-35 ⇾ chlorine-35 + positron
- phosphorus-35 + e ⇾ sulfur-35
- sulfur-35 + e ⇾ chlorine-35
- A freshly prepared sample of yttrium-90 undergoes 7.6 × 105 disintegrations per minute (dpm) at a certain time. Exactly 14 days later, the same sample undergoes 1.6 × 104 dpm. The half-life of yttrium-90 is:
- 0.20 day
- 2.5 day
- 2.7 day
- 3.8 day
- 14 day