Nursing Elites

1. In a closed system with a gas at constant volume, what will happen to the temperature if the pressure is increased?

• A. The temperature will stay the same
• B. The temperature will decrease
• C. The temperature will increase
• D. It cannot be determined with the information given

Correct answer: C

Rationale: In a closed system with a gas at constant volume, according to Gay-Lussac's law, the temperature of a gas is directly proportional to its pressure. When the pressure is increased, the temperature of the gas will also increase. This relationship is a direct consequence of the ideal gas law, where pressure and temperature are directly proportional when volume is held constant. Therefore, as pressure increases in a closed system with constant volume, the temperature of the gas will increase. Choices A, B, and D are incorrect. The temperature will not stay the same (Choice A) or decrease (Choice B) when the pressure is increased in this scenario. The relationship between pressure and temperature in a closed system with constant volume allows for a definitive conclusion about the increase in temperature when pressure is increased, making Choice D, which suggests inability to determine, incorrect.

2. What is the process of separating a mixture based on the different boiling points of its components called?

• A. Filtration
• B. Chromatography
• C. Distillation
• D. Centrifugation

Correct answer: C

Rationale: Distillation is the process of separating a mixture based on the different boiling points of its components. During distillation, the mixture is heated to vaporize the component with the lowest boiling point first. The vapor is then cooled and condensed back into a liquid, allowing for the collection of fractions with different boiling ranges. This technique is effective for separating components that have significantly different boiling points. Filtration (Choice A) is a method used to separate solids from liquids or gases using a filter medium. Chromatography (Choice B) is a technique used to separate components of a mixture based on their differential affinities to a stationary phase and a mobile phase. Centrifugation (Choice D) is a process of separating particles from a solution based on differences in size, shape, density, and viscosity by spinning the mixture at high speeds.

3. How many moles of oxygen are required to completely react with 5 moles of propane (C3H8) in the combustion reaction?

• A. 5 moles
• B. 10 moles
• C. 15 moles
• D. 20 moles

Correct answer: C

Rationale: In the balanced chemical equation for the combustion of propane (C3H8): C3H8 + 5O2 → 3CO2 + 4H2O, 1 mole of propane (C3H8) reacts with 5 moles of oxygen (O2). To determine the moles of oxygen required to react with 5 moles of propane, we use the molar ratio: 5 moles propane x 5 moles oxygen / 1 mole propane = 25 moles oxygen. However, since the question specifically asks for the moles of oxygen needed to react with 5 moles of propane, the correct answer is 15 moles of oxygen. Choice A, 5 moles, is incorrect because this is the amount of propane provided, not the oxygen required. Choice B, 10 moles, is incorrect as it does not correspond to the molar ratio in the balanced equation. Choice D, 20 moles, is incorrect as it is not in line with the stoichiometry of the reaction.

4. A rocket engine expels hot gases backwards. What principle explains the rocket's forward motion?

• A. Newton's first law of motion
• B. Newton's second law of motion
• C. Newton's third law of motion
• D. Law of conservation of energy

Correct answer: C

Rationale: Newton's third law of motion states that for every action, there is an equal and opposite reaction. In the case of a rocket engine expelling hot gases backwards, the action is the expulsion of gases, and the reaction is the forward motion of the rocket. The hot gases being expelled act as the action force, propelling the rocket in the opposite direction as the reaction force, resulting in the rocket's forward motion. Newton's first law of motion (Choice A) pertains to inertia, stating that an object in motion will stay in motion unless acted upon by an external force. Newton's second law of motion (Choice B) relates force, mass, and acceleration, which is not directly applicable to the scenario of a rocket engine propulsion. The law of conservation of energy (Choice D) is a fundamental principle stating that energy cannot be created or destroyed but can only be transformed, which does not directly explain the forward motion of the rocket in this context.

5. What is the main function of the pancreas?

• A. To store food and break it down into smaller pieces
• B. To absorb nutrients into the bloodstream
• C. To produce enzymes that help digest food
• D. To regulate blood sugar levels

Correct answer: C

Rationale: The main function of the pancreas is to produce digestive enzymes that aid in breaking down carbohydrates, fats, and proteins in food. These enzymes are essential for the digestion and absorption of nutrients in the small intestine. While the pancreas also plays a role in regulating blood sugar levels by producing insulin and glucagon, its primary function is to produce enzymes for food digestion. Options A and B are incorrect as the pancreas is not involved in storing food or absorbing nutrients into the bloodstream.

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