Nursing Elites

1. What is 119 K in degrees Celsius?

• A. 32°C
• B. -154°C
• C. 154°C
• D. 0°C

Correct answer: B

Rationale: To convert Kelvin (K) to Celsius (°C), you subtract 273.15 from the Kelvin value. Therefore, 119 K - 273.15 = -154.15°C. The negative sign indicates that the temperature is below freezing. When rounded to the nearest whole number, -154.15°C is approximately -154°C. Choice A and Choice C are incorrect as they do not reflect the correct conversion from Kelvin to Celsius. Choice D is incorrect as it corresponds to the freezing point of water in Celsius, not the conversion of 119 K.

2. Which substance shows a decrease in solubility in water with an increase in temperature?

• A. NaCl
• B. O
• C. KI
• D. CaCl

Correct answer: C

Rationale: Potassium iodide (KI) shows a decrease in solubility in water with an increase in temperature. This is due to the dissolution of KI in water being an endothermic process. When the temperature rises, the equilibrium shifts toward the solid state, leading to a decrease in solubility. Therefore, as the temperature increases, KI becomes less soluble in water. Choice A (NaCl) and Choice D (CaCl) do not exhibit a decrease in solubility with an increase in temperature. NaCl and CaCl are generally more soluble in water at higher temperatures. Choice B (Oxygen) is a gas and not typically considered in solubility discussions involving solids or liquids dissolving in water.

3. What is the boiling point of water in °C?

• A. 90°C
• B. 100°C
• C. 95°C
• D. 80°C

Correct answer: B

Rationale: The correct answer is 100°C. The boiling point of water in Celsius is 100°C, which is standard at sea level. This is the temperature at which water changes from a liquid to a gas phase under standard atmospheric pressure. Choice A (90°C), Choice C (95°C), and Choice D (80°C) are incorrect because they do not represent the standard boiling point of water at sea level.

4. What term refers to the average of the masses of each of its isotopes as they occur in nature?

• A. Atomic number
• B. Mass number
• C. Atomic mass
• D. Neutron number

Correct answer: C

Rationale: The correct answer is atomic mass. Atomic mass is the weighted average of the masses of an element's isotopes. It takes into account the abundance of each isotope in nature to provide a more accurate representation of the element's overall mass. Choice A, atomic number, represents the number of protons in an atom. Choice B, mass number, refers to the total number of protons and neutrons in an atom's nucleus. Choice D, neutron number, specifically focuses on the count of neutrons in an atom's nucleus. These choices do not directly relate to the average mass of isotopes as asked in the question.

5. Which number represents the number of protons in an element?

• A. Atomic mass
• B. Mass number
• C. Atomic number
• D. Proton number

Correct answer: C

Rationale: The correct answer is C: Atomic number. The atomic number corresponds to the number of protons in an element. Protons are positively charged subatomic particles found in the nucleus of an atom. Each element has a unique atomic number, which defines its identity based on the number of protons it contains. Choice A, Atomic mass, is incorrect as it refers to the average mass of an atom of an element. Choice B, Mass number, represents the total number of protons and neutrons in an atom's nucleus. Choice D, Proton number, is not a commonly used term in chemistry to indicate the number of protons.

Similar Questions