Which of the following is a true statement about sodium chloride (NaCl)?
- A. It is a gas at room temperature.
- B. It is a compound formed from two elements.
- C. It is a mixture formed from two different compounds.
- D. It is an element that is unstable and reactive.
Correct Answer & Rationale
Correct Answer: B
Sodium chloride (NaCl) is indeed a compound formed from two elements: sodium (Na) and chlorine (Cl), which combine in a fixed ratio through ionic bonding. Option A is incorrect; NaCl is a solid at room temperature, not a gas. Option C misrepresents NaCl as a mixture, but it is a pure compound, not formed from different compounds. Option D inaccurately describes NaCl as an element; it is a stable compound, not unstable or reactive under normal conditions. Thus, option B accurately reflects the nature of sodium chloride.
Sodium chloride (NaCl) is indeed a compound formed from two elements: sodium (Na) and chlorine (Cl), which combine in a fixed ratio through ionic bonding. Option A is incorrect; NaCl is a solid at room temperature, not a gas. Option C misrepresents NaCl as a mixture, but it is a pure compound, not formed from different compounds. Option D inaccurately describes NaCl as an element; it is a stable compound, not unstable or reactive under normal conditions. Thus, option B accurately reflects the nature of sodium chloride.
Other Related Questions
Based on the food web shown, which of the following is true about the feeding relationships?
- A. Bivalves have no natural predators in the Chesapeake Bay ecosystem.
- B. Wading birds are herbivores that eat aquatic vegetation.
- C. Phytoplankton are producers that convert light energy into organic matter.
- D. Sea ducks are primary consumers that eat only bald eagles.
Correct Answer & Rationale
Correct Answer: C
In the food web, phytoplankton are classified as producers because they perform photosynthesis, converting light energy into organic matter. This foundational role supports the entire ecosystem. Option A is incorrect; bivalves often have predators, such as certain fish and birds, that feed on them. Option B misclassifies wading birds, which are carnivores that primarily feed on small fish and invertebrates, not herbivores. Option D is misleading, as sea ducks are primary consumers but do not exclusively eat bald eagles; they primarily consume aquatic plants and invertebrates. Thus, option C accurately reflects the role of phytoplankton in the ecosystem.
In the food web, phytoplankton are classified as producers because they perform photosynthesis, converting light energy into organic matter. This foundational role supports the entire ecosystem. Option A is incorrect; bivalves often have predators, such as certain fish and birds, that feed on them. Option B misclassifies wading birds, which are carnivores that primarily feed on small fish and invertebrates, not herbivores. Option D is misleading, as sea ducks are primary consumers but do not exclusively eat bald eagles; they primarily consume aquatic plants and invertebrates. Thus, option C accurately reflects the role of phytoplankton in the ecosystem.
Which of the following plant structures are specialized for the absorption of water and nutrients from the environment?
- A. Roots
- B. Leaves
- C. Flowers
- D. Stems
Correct Answer & Rationale
Correct Answer: A
Roots are specialized structures designed for the absorption of water and nutrients from the soil, featuring a large surface area and root hairs that enhance their efficiency. Leaves primarily function in photosynthesis and gas exchange, not nutrient absorption. Flowers are reproductive structures that facilitate pollination and seed production, playing no direct role in nutrient uptake. Stems support the plant and transport water and nutrients between roots and leaves, but they do not absorb them. Thus, roots are uniquely equipped for this essential task.
Roots are specialized structures designed for the absorption of water and nutrients from the soil, featuring a large surface area and root hairs that enhance their efficiency. Leaves primarily function in photosynthesis and gas exchange, not nutrient absorption. Flowers are reproductive structures that facilitate pollination and seed production, playing no direct role in nutrient uptake. Stems support the plant and transport water and nutrients between roots and leaves, but they do not absorb them. Thus, roots are uniquely equipped for this essential task.
Which of the following is the best way to measure the volume of an irregularly shaped solid, such as a rock?
- A. Use a balance to measure the mass of the rock and divide by its density.
- B. Place the rock in a graduated cylinder containing water and measure the change in water level.
- C. Use a ruler to measure the length, width, and height of the rock and multiply them together.
- D. Use a stopwatch to measure how long it takes the rock to fall a certain distance and calculate its volume from its speed.
Correct Answer & Rationale
Correct Answer: B
Measuring the change in water level in a graduated cylinder provides an accurate method for determining the volume of an irregularly shaped solid, as it directly accounts for the object's displacement of water. Using a balance to measure mass and dividing by density (Option A) only works if the density is known, which is not practical for irregular shapes. Measuring dimensions (Option C) is ineffective since irregular shapes do not conform to simple geometric formulas. Lastly, using a stopwatch to calculate volume from falling speed (Option D) is unrelated to volume measurement and introduces unnecessary complexity.
Measuring the change in water level in a graduated cylinder provides an accurate method for determining the volume of an irregularly shaped solid, as it directly accounts for the object's displacement of water. Using a balance to measure mass and dividing by density (Option A) only works if the density is known, which is not practical for irregular shapes. Measuring dimensions (Option C) is ineffective since irregular shapes do not conform to simple geometric formulas. Lastly, using a stopwatch to calculate volume from falling speed (Option D) is unrelated to volume measurement and introduces unnecessary complexity.
The pitch of a sound is related to which of the following properties of a sound wave?
- A. Speed
- B. Frequency
- C. Amplitude
- D. Energy
Correct Answer & Rationale
Correct Answer: B
The pitch of a sound is directly related to its frequency, which refers to how many sound wave cycles occur in one second. Higher frequencies produce higher pitches, while lower frequencies result in lower pitches. Option A, speed, refers to how fast sound travels through a medium but does not affect pitch. Option C, amplitude, relates to the loudness or intensity of a sound rather than its pitch. Option D, energy, is associated with the overall power of the sound wave but does not determine pitch. Thus, frequency is the key property that defines the pitch of a sound.
The pitch of a sound is directly related to its frequency, which refers to how many sound wave cycles occur in one second. Higher frequencies produce higher pitches, while lower frequencies result in lower pitches. Option A, speed, refers to how fast sound travels through a medium but does not affect pitch. Option C, amplitude, relates to the loudness or intensity of a sound rather than its pitch. Option D, energy, is associated with the overall power of the sound wave but does not determine pitch. Thus, frequency is the key property that defines the pitch of a sound.