What term describes how much of each component is present in a mixture?

• A. Percentage
• B. Concentration
• C. Ratio
• D. Density

Answer: (B)

Concentration describes how much of each component is present in a mixture. It captures the amount of a substance relative to the total mixture or to another component, which is exactly what you’re being asked about. In practice, concentration can be expressed in several ways—percent by weight or volume, parts per million, or as a ratio—covering the different ways we quantify how much of each component exists in the mix. For hazmat scenarios, knowing the concentration of a contaminant in air (for example, ppm or mg/m3) tells you the exposure level and potential risk. A percentage is a specific way to express concentration, but the broader term that fits the question is concentration. The other options don’t fit as well: a ratio compares two amounts but doesn’t convey the overall composition of the mixture; density is mass per volume and describes a physical property of a substance, not its composition.