Chemistry HESI A2 Practice Test - Nurselytic

Correct Answer: B

Rationale: The normal body temperature for humans is 98.6°F, which is equivalent to 37°C. This temperature is considered the average baseline for most individuals when measured orally.
Choice A (96°F) is too low for normal body temperature.
Choice C (100°F) is too high for normal body temperature.
Choice D (95°F) is also lower than the normal body temperature range.
Therefore, the correct answer is B, 98.6°F.

Correct Answer: B

Rationale: Medical isotopes used in diagnosis and treatment need to have a relatively short half-life to minimize radiation exposure to patients. If the half-life were too long (such as many years) or even years-long, the radiation would persist for too long and could be harmful to the patient. Seconds-long half-lives would not provide enough time for the isotope to be effective. Days-long half-lives strike a balance between providing enough time for the isotope to be used effectively and minimizing radiation exposure.

Correct Answer: B

Rationale: The correct answer is B: 8. Carbon-14 is an isotope of carbon with 6 protons and 8 neutrons.
To determine the number of neutrons in an atom, subtract the atomic number (number of protons) from the mass number. In this case, the mass number of carbon-14 is 14, and the atomic number of carbon is 6.
Therefore, 14 (mass number) - 6 (atomic number) = 8 neutrons.

Choices A, C, and D are incorrect because they do not reflect the correct number of neutrons in a carbon-14 atom.

Correct Answer: A

Rationale: Molarity is defined as the number of moles of solute per liter of solution. A molarity of 5 M indicates there are 5 moles of salt in 1 liter of the solution. Since the volume of the solution is 0 liters, multiplying the molarity by 0 liters results in 0 moles of salt (5 moles/L x 0 L = 0 moles).
Therefore, the correct answer is 0. Option B, 1.5, is incorrect because it doesn't consider the volume being 0 liters. Options C and D, 2 and 3 respectively, are also incorrect as they do not account for the zero volume of the solution. Hence, there are no moles of salt present in 0 liters of the solution.

Correct Answer: C

Rationale: An alpha particle consists of two protons and two neutrons, resulting in a total charge of +2 due to the presence of two positively charged protons.
Therefore, the correct answer is C, indicating a charge of +2.

Choices A, B, and D are incorrect because an alpha particle is positively charged due to the two protons it contains, resulting in a charge of +2.