The mass of the flow is affected by what property of the fuel?

• A. The density of the fuel
• B. The color of the fuel
• C. The pH of the fuel
• D. The odour of the fuel

Answer: (A)

The mass flow rate of fuel through a line depends on two things: how much volume is moving per second and how much mass that volume contains. Mass flow = density × volumetric flow rate. So, for a given volumetric flow, a denser fuel carries more mass per second, while a lighter fuel carries less. Temperature can change density, so mass flow can vary with temperature even if the volumetric flow is the same. The other properties listed—color, pH, and odor—don’t affect how much mass passes per unit time, so they don’t influence the mass flow.