Nursing Elites

1. What is the difference between a pure substance and a mixture?

• A. Pure substances have a fixed composition, mixtures don't.
• B. Mixtures have a fixed composition, pure substances don't.
• C. Pure substances can be in any state, mixtures are not always solids.
• D. Pure substances are always elements, mixtures are always compounds.

Correct answer: A

Rationale: Pure substances have a definite and constant composition, meaning they are made up of only one type of atom or molecule with fixed proportions. This composition does not vary. On the other hand, mixtures are composed of two or more substances physically combined. The components of a mixture can be present in varying proportions, leading to a variable composition. Choice A is correct as it accurately distinguishes between pure substances and mixtures based on the fixed composition of pure substances and the variable composition of mixtures. Choice B is incorrect because mixtures, not pure substances, have variable compositions. Choice C is incorrect as both pure substances and mixtures can exist in different states. Choice D is incorrect because pure substances can be compounds as well, not exclusively elements, and mixtures can contain elements and compounds.

2. A woman’s dinner bill comes to $48.30. If she adds a 20% tip, which of the following will be her total bill?

• A. $9.66
• B. $38.64
• C. $48.30
• D. $57.96

Correct answer: D

Rationale: To calculate the total bill after adding a 20% tip, you need to find 120% of the original bill. This is because adding a 20% tip means paying 120% of the bill. So, $48.30 × 120/100 = $57.96. Therefore, the correct answer is $57.96. Choice A ($9.66) is incorrect as it represents only the 20% tip amount. Choice B ($38.64) is incorrect as it is the original bill amount without the tip. Choice C ($48.30) is incorrect as it is the original bill amount and does not include the additional 20% tip.

3. When should you redirect your dog's biting behavior?

• A. When your dog bites something inappropriate
• B. When your dog barks at strangers
• C. When your dog is lying down
• D. When your dog is eating

Correct answer: A

Rationale: You should redirect your dog's biting behavior when it bites something inappropriate. This can include redirecting its attention to an appropriate chew toy and using biting deterrent spray. The extract suggests that redirecting biting behavior is necessary when your dog bites something it shouldn't.

4. The acceleration of a falling object due to gravity has been proven to be 9.8 m/s². A scientist drops a cactus four times and measures the acceleration with an accelerometer and gets the following results: 9.79 m/s², 9.81 m/s², 9.80 m/s², and 9.78 m/s². Which of the following accurately describes the measurements?

• A. They're both accurate and precise.
• B. They're accurate but not precise.
• C. They're precise but not accurate.
• D. They're neither accurate nor precise.

Correct answer: A

Rationale: The measurements are both close to the actual value (accurate) and consistent with each other (precise). Accuracy refers to how close a measurement is to the true value, and precision refers to the reproducibility or consistency of the measurements. In this case, the measured values are all very close to the actual value of 9.8 m/s², indicating accuracy. Additionally, the measurements are clustered closely together, demonstrating precision. Therefore, the measurements are both accurate and precise, making choice A the correct answer. Choices B, C, and D are incorrect because the measurements exhibit both accuracy and precision, as they are close to the true value and also consistent with each other.

5. Simplify the following expression: 6 + 7 × 3 - 4 × 2

• A. -42
• B. -20
• C. 23
• D. 20

Correct answer: B

Rationale: ollow the order of operations (PEMDAS: Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right)): Multiply: 7 × 3 = 21, and 4 × 2 = 8 Perform addition and subtraction: 6 + 21 - 8 = 19 Thus, the simplified expression equals 19.

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