Nursing Elites

1. Balance the chemical equation: C4H10 + O2 → CO2 + H2O. What is the coefficient for oxygen?

• A. 5
• B. 6
• C. 7
• D. 8

Correct answer: B

Rationale: To balance the chemical equation, we need to ensure that the number of each type of atom is the same on both sides of the equation. In this case, there are 10 oxygen atoms on the right side (5 in CO2 and 5 in H2O). To balance this, we need to add a coefficient of 6 in front of O2 on the left side, resulting in 6 O2 molecules. This change will give us a total of 12 oxygen atoms on both sides, making the equation balanced. Choice A (5) is incorrect because it does not account for all the oxygen atoms present in the products. Choices C (7) and D (8) are incorrect as they would result in an imbalance in the number of oxygen atoms on both sides of the equation.

2. What is the primary function of the epiglottis in the respiratory system?

• A. Filtration of air
• B. Production of mucus
• C. Prevention of food entering the trachea
• D. Oxygen exchange in the alveoli

Correct answer: C

Rationale: The primary function of the epiglottis in the respiratory system is to prevent food from entering the trachea. During swallowing, the epiglottis covers the opening of the trachea, guiding food down the esophagus to the stomach and preventing it from entering the airway. This mechanism safeguards the respiratory system from foreign objects, ensuring proper air passage and avoiding potential choking hazards. Choices A, B, and D are incorrect: A) Filtration of air is mainly performed by the nasal hairs and the mucous membranes of the respiratory tract. B) Production of mucus is primarily carried out by the mucous glands in the respiratory system to trap particles and humidify the air. D) Oxygen exchange in the alveoli occurs in the lungs and is related to the process of respiration, not the function of the epiglottis.

3. What is the product of the complete combustion of propane (C3H8)?

• A. CO2
• B. CO
• C. CH4
• D. C

Correct answer: A

Rationale: The complete combustion of propane (C3H8) results in the production of carbon dioxide (CO2) and water. When a hydrocarbon such as propane undergoes complete combustion, the carbon atoms combine with oxygen to form CO2. This makes choice A, CO2, the correct answer. Choices B, C, and D are incorrect as CO is carbon monoxide, CH4 is methane, and C is elemental carbon, none of which are the primary product of the complete combustion of propane.

4. Which of the following vessels is responsible for transporting blood from the heart to the lungs?

• A. Pulmonary vein
• B. Pulmonary artery
• C. Aorta
• D. Superior vena cava

Correct answer: B

Rationale: The correct answer is B, Pulmonary artery. The pulmonary artery carries deoxygenated blood from the heart's right ventricle to the lungs for oxygenation. This blood then undergoes the gas exchange process in the lungs, where carbon dioxide is removed, and oxygen is absorbed. The pulmonary vein, identified in choice A, carries oxygenated blood from the lungs back to the heart, which is the opposite direction of the blood flow specified in the question. Choice C, Aorta, is responsible for carrying oxygen-rich blood from the heart's left ventricle to the rest of the body, not to the lungs. Choice D, Superior vena cava, returns deoxygenated blood from the upper body to the heart's right atrium, but it does not transport blood specifically to the lungs as requested in the question.

5. What is the main function of the respiratory system?

• A. To absorb nutrients
• B. To exchange gases
• C. To transport oxygen
• D. To regulate blood pressure

Correct answer: B

Rationale: The main function of the respiratory system is to exchange gases, primarily oxygen and carbon dioxide, between the body and the environment. Option A, 'To absorb nutrients,' is incorrect because the respiratory system is not involved in nutrient absorption. Option C, 'To transport oxygen,' is partially correct, but it doesn't encompass the complete role of gas exchange that includes both oxygen and carbon dioxide. Option D, 'To regulate blood pressure,' is incorrect as blood pressure regulation is primarily controlled by the cardiovascular system, not the respiratory system.

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