Nursing Elites

1. How many neutrons are in an atom of helium-4?

• A. 2
• B. 3
• C. 4
• D. 6

Correct answer: A

Rationale: The atomic number of helium is 2, indicating it has 2 protons. Helium-4, the most common isotope of helium, has 2 neutrons in addition to its 2 protons. Therefore, the correct answer is 2 neutrons in an atom of helium-4. Choice B, C, and D are incorrect as they do not match the correct composition of helium-4, which consists of 2 protons and 2 neutrons.

2. Which element has an atomic mass greater than that of sodium?

• A. Boron
• B. Oxygen
• C. Fluorine
• D. Silicon

Correct answer: D

Rationale: Silicon has an atomic mass greater than that of sodium. The atomic mass of silicon is approximately 28.0855 u, whereas the atomic mass of sodium is approximately 22.9898 u. Therefore, silicon has a greater atomic mass compared to sodium. Boron, Oxygen, and Fluorine have atomic masses lower than sodium, making them incorrect choices in this context.

3. In which state of matter are particles packed tightly together in a fixed position?

• A. Liquid
• B. Solid
• C. Gas
• D. Plasma

Correct answer: B

Rationale: In a 'solid' state, particles are tightly packed in fixed positions, maintaining a definite shape and volume. This arrangement allows solids to maintain a rigid structure. Liquids have particles that are close together but can move past each other, giving them the ability to flow and take the shape of their container. Gases have particles that are far apart and move freely, leading to their ability to expand to fill any container. Plasma is an ionized gas where particles have high energy levels and are not packed tightly together, making it an uncommon state of matter on Earth.

4. How can the reaction rate of a chemical reaction be increased?

• A. Increase the temperature
• B. Increase the surface area
• C. Increase the concentration of reactants
• D. Add a catalyst

Correct answer: A

Rationale: To increase the reaction rate of a chemical reaction, one effective method is to increase the temperature. Raising the temperature provides more energy to the reacting particles, enabling them to collide more frequently and with higher energy, leading to an increase in the reaction rate. While increasing the surface area, concentration of reactants, and adding a catalyst are strategies that can also enhance the reaction rate, raising the temperature has the most direct and immediate impact. Increasing the surface area allows for more contact between reactants, increasing the concentration provides more reactant particles to collide, and adding a catalyst lowers the activation energy required for the reaction to occur. However, these methods may not have as immediate and significant an effect as increasing the temperature.

5. What is the name of the device that separates gaseous ions by their mass-to-charge ratio?

• A. mass spectrometer
• B. interferometer
• C. magnetometer
• D. capacitance meter

Correct answer: A

Rationale: A mass spectrometer is a device specifically designed to separate gaseous ions based on their mass-to-charge ratio. This separation process involves ionization, acceleration of the sample, and the deflection of ions in a magnetic field according to their mass-to-charge ratio. The other options, 'interferometer,' 'magnetometer,' and 'capacitance meter,' do not perform the specific function of separating gaseous ions based on their mass-to-charge ratio, making them incorrect choices.

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