How are Ls and Gs defined in terms of flowrate?

The correct choice defines Ls and Gs as mass or molar flowrate divided by flow area, which effectively relates the flowrate of a substance to the cross-sectional area through which it flows.

In fluid dynamics, Ls typically represents a liquid phase flowrate, while Gs represents a gas phase flowrate. By dividing these flowrates (mass or molar) by the flow area, you obtain a velocity term that quantifies how fast the fluid is moving through that area. This relationship is crucial in many engineering applications, including sizing pipes and optimizing flow processes.

The other options do not accurately represent the standard definitions of Ls and Gs in terms of flowrate. For instance, using pressure in the denominator does not correspond to flow characteristics; pressure is a separate parameter that influences flowrate but is not directly interchangeable with flow area in this context. Similarly, while molar flowrate by flow area might seem relevant, it does not encompass the broader definition that includes mass flowrate, which is equally important in various chemical engineering applications. Therefore, recognizing Ls and Gs as flowrate per unit area provides a more complete understanding of their definitions.