Nursing Elites

1. What is the term for the particles moving within a substance?

• A. Ions
• B. Atoms
• C. Molecules
• D. Kinetic energy

Correct answer: C

Rationale: The term for the particles moving within a substance is typically 'molecules' or 'atoms,' depending on the state of matter. In this context, 'molecules' represent the particles moving around within a substance, especially in the liquid and gas states, while 'atoms' are the fundamental building blocks of matter. 'Ions' are charged particles that can be present in a substance but are not necessarily the primary particles in motion. 'Kinetic energy' is not a term used to describe the particles themselves but rather the energy associated with their motion.

2. Which of the following is unique to covalent bonds?

• A. Most covalent bonds are formed between the elements H, F, N, and O.
• B. Covalent bonds are dependent on forming dipoles.
• C. Bonding electrons are shared between two or more atoms.
• D. Molecules with covalent bonds tend to have a crystalline solid structure.

Correct answer: C

Rationale: The correct answer is C: 'Bonding electrons are shared between two or more atoms.' This statement is unique to covalent bonds. In covalent bonds, atoms share electrons to achieve a stable electron configuration, which leads to the formation of a bond. This sharing of electrons is a fundamental characteristic of covalent bonds and distinguishes them from other types of chemical bonds, such as ionic bonds, where electrons are transferred rather than shared. Choices A, B, and D do not represent unique characteristics of covalent bonds. Choice A describes some common elements involved in covalent bonds, choice B refers to the concept of dipoles, which can also exist in other types of bonds, and choice D describes a property of molecules (crystalline solid structure) that is not exclusive to covalent bonds.

3. Which property of a substance resists a change in its shape?

• A. Density
• B. Mass
• C. Inertia
• D. Elasticity

Correct answer: D

Rationale: Elasticity refers to a material's ability to resist deformation and return to its original shape after stress is applied. It is the property that resists a change in shape. Density is the mass per unit volume of a substance. Mass is the amount of matter in an object, while inertia is the tendency of an object to resist changes in its state of motion. Viscosity, not mentioned in the question, is the resistance of a fluid to flow, not shape change.

4. What effect does a catalyst have on a chemical reaction?

• A. It speeds up the reaction.
• B. It slows down the reaction.
• C. It makes a reaction go in reverse.
• D. It prevents a reaction from taking place.

Correct answer: A

Rationale: A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It works by providing an alternate pathway for the reaction to occur, lowering the activation energy needed for the reaction to proceed. As a result, more reactant molecules can overcome this energy barrier and participate in the reaction, leading to a faster overall reaction rate. This explanation contradicts choices B, C, and D as a catalyst does not slow down, reverse, or prevent a reaction; instead, it accelerates the reaction by facilitating a more efficient route for the reaction to take place. Therefore, the correct answer is that a catalyst speeds up the reaction.

5. Which organelle provides energy for cellular functions?

• A. Nucleus
• B. Cell membrane
• C. Mitochondria
• D. Cytoplasm

Correct answer: C

Rationale: The correct answer is C, Mitochondria. Mitochondria are often referred to as the powerhouse of the cell as they produce energy in the form of ATP through cellular respiration. This process is essential for various cellular functions, making mitochondria crucial for energy production within the cell. Choice A, Nucleus, is incorrect as the nucleus is responsible for housing the cell's genetic material and controlling cellular activities but not for energy production. Choice B, Cell membrane, is incorrect as it is primarily involved in maintaining cell integrity and regulating the passage of substances in and out of the cell, not in energy production. Choice D, Cytoplasm, is incorrect as it is the jelly-like substance that fills the cell and is the site of many metabolic pathways, but it is not the specific organelle responsible for energy production.

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