Nursing Elites

1. What is the name of the force that holds ionic compounds together?

• A. Covalent bonds
• B. Ionic bonds
• C. Hydrogen bonds
• D. Metallic bonds

Correct answer: B

Rationale: Ionic bonds are the forces that hold ionic compounds together. In ionic compounds, positively and negatively charged ions are held together by electrostatic forces of attraction, forming a stable structure. Covalent bonds involve the sharing of electrons between atoms, not the transfer of electrons like in ionic bonds. Hydrogen bonds are a type of intermolecular force, not the primary force in holding ionic compounds together. Metallic bonds are found in metals and involve a 'sea of electrons' that hold metal atoms together, different from the electrostatic attraction between ions in ionic compounds.

2. What does a blood sample with a pH of 3 indicate?

• A. It is strongly acidic.
• B. It is strongly basic.
• C. It is weakly acidic.
• D. It is weakly basic.

Correct answer: A

Rationale: A blood pH of 3 is significantly low, indicating a strong acidity level. The normal blood pH range is 7.35 to 7.45; therefore, a pH of 3 is far below the normal range, showing a highly acidic condition in the blood sample. Choice B is incorrect because a pH of 3 is not basic at all. Choice C is incorrect as a pH of 3 is not weakly acidic but strongly acidic. Choice D is wrong as a blood pH of 3 does not indicate a weakly basic condition.

3. Which of these represents a strong acid?

• A. CH₃COOH
• B. H₂SO₄
• C. NH₃
• D. KOH

Correct answer: B

Rationale: Among the options provided, H₂SO₄ (sulfuric acid) represents a strong acid. Strong acids completely ionize in water to produce a high concentration of H+ ions. Sulfuric acid is a strong acid known for its ability to dissociate almost completely in water, making it a strong acid. Choice A, CH₃COOH (acetic acid), is a weak acid that only partially dissociates in water. Choices C and D, NH₃ (ammonia) and KOH (potassium hydroxide), are bases and not acids.

4. Which of the following best describes an endothermic reaction?

• A. A reaction that absorbs heat
• B. A reaction that releases heat
• C. A reaction that does not involve heat
• D. A reaction that remains at a constant temperature

Correct answer: A

Rationale: An endothermic reaction is a process that absorbs heat from its surroundings. When a reaction absorbs heat, it leads to a decrease in the temperature of the surroundings, making choice A the correct description. In an endothermic reaction, energy is taken in from the surroundings, resulting in a decrease in temperature around the reaction site. Choice B is incorrect because a reaction that releases heat is known as an exothermic reaction. Choice C is incorrect as all reactions involve heat to some extent. Choice D is incorrect as an endothermic reaction does not remain at a constant temperature but rather absorbs heat, leading to a temperature decrease in the surroundings.

5. What type of intermolecular force is a dipole attraction?

• A. Strong
• B. Weak
• C. Medium
• D. Very strong

Correct answer: B

Rationale: A dipole attraction is considered a weak intermolecular force. It occurs between molecules with permanent dipoles, where the positive end of one molecule is attracted to the negative end of another molecule. While dipole-dipole interactions are stronger than dispersion forces, they are weaker than hydrogen bonding or ion-dipole interactions. Therefore, the correct answer is 'Weak.' Choices A, C, and D are incorrect because dipole attractions are not classified as strong, medium, or very strong intermolecular forces, but rather fall into the category of weak intermolecular forces.

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