Nursing Elites

1. What is the term for the process of separating the components of a solution based on their different rates of movement through a medium?

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

Correct answer: c

Rationale: Chromatography is a technique used to separate the components of a solution based on their different rates of movement through a medium. The other choices are different separation techniques.

2. What type of intermolecular force is responsible for the high surface tension of water?

• A. Hydrogen bonding
• B. London dispersion forces
• C. Ionic bonding
• D. Metallic bonding

Correct answer: A

Rationale: The high surface tension of water is due to the strong hydrogen bonding between water molecules. Hydrogen bonding is a type of intermolecular force that occurs when a hydrogen atom is covalently bonded to a highly electronegative atom (such as oxygen in water) and is attracted to another electronegative atom nearby. This results in a strong attraction between water molecules at the surface, leading to a high surface tension.

3. A balanced chemical equation for the reaction between sodium and chlorine to form sodium chloride is:

• A. Na + Cl2 -> NaCl
• B. 2Na + Cl2 -> 2NaCl
• C. Na2 + Cl -> 2NaCl
• D. Na + 2Cl -> NaCl2

Correct answer: A

Rationale: The correct balanced chemical equation for the reaction between sodium and chlorine to form sodium chloride is '2Na + Cl2 -> 2NaCl'. This equation is balanced as it shows that 2 atoms of sodium react with 1 molecule of chlorine gas to produce 2 molecules of sodium chloride. Option A 'Na + Cl2 -> NaCl' is incorrect as it does not balance the number of atoms on both sides of the equation. It only shows 1 atom of sodium reacting with 1 molecule of chlorine, which is not a balanced representation of the chemical reaction. Therefore, option B is the correct choice for this question.

4. Melatonin is a hormone produced by the pineal gland. What is its primary function?

• A. Regulate blood pressure
• B. Stimulate the digestive system
• C. Control sleep-wake cycles
• D. Maintain bone density

Correct answer: C

Rationale: The correct answer is C: 'Control sleep-wake cycles.' Melatonin is a hormone that plays a key role in regulating the body's sleep-wake cycle, also known as the circadian rhythm. The pineal gland releases melatonin in response to darkness, helping to signal to the body that it is time to sleep. By influencing the timing and quality of sleep, melatonin helps maintain a healthy sleep pattern and overall well-being. While blood pressure, digestive system stimulation, and bone density are important functions in the body, melatonin's primary function is to regulate the sleep-wake cycle.

5. A syringe holds 3ml of liquid. How many syringes are needed to measure 15ml of liquid?

• A. 3
• B. 5
• C. 7
• D. 9

Correct answer: B

Rationale: Divide the total liquid volume (15ml) by the syringe capacity (3ml/syringe) to get 5 syringes.

6. In an SN2 reaction, the rate of the reaction is affected by

• A. Only the concentration of the nucleophile
• B. Only the concentration of the electrophile
• C. Neither the concentration of the nucleophile nor the electrophile
• D. Both the concentration of the nucleophile and the electrophile

Correct answer: D

Rationale: In an SN2 reaction, the rate of the reaction is affected by both the concentration of the nucleophile and the electrophile. This is because in an SN2 reaction, the nucleophile directly attacks the electrophilic center, leading to the formation of the product. A higher concentration of nucleophile increases the chances of successful collisions with the electrophile, thereby increasing the reaction rate. Similarly, a higher concentration of the electrophile provides more reaction sites for the nucleophile to attack, also increasing the rate of the reaction. Therefore, both the nucleophile and electrophile concentrations play crucial roles in determining the rate of an SN2 reaction.

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