Final answer:
The liter (L) is the SI unit commonly used to describe the volume of a liquid and gas in a laboratory setting.
Step-by-step explanation:
The SI unit commonly used to describe the volume of a liquid and gas is the liter (L). The liter (L) is the SI unit commonly used to describe the volume of a liquid and gas in a laboratory setting. While the base SI unit for volume is the cubic meter (m³), it is impractically large for use in most laboratory settings.
Instead, the liter, which is defined as 1,000 cubic centimeters (cm³) or 1/1,000th of a cubic meter, is commonly used. For smaller volumes, the milliliter (mL), which is equivalent to a cubic centimeter, is also frequently used. These units are convenient for measuring laboratory volumes of fluids and gases, aligning with common practices in chemistry.