🔍 Key Concepts

• Meaning of emulsion and how oil and water can form an emulsion in machinery systems • What property of an oil describes how easily it will separate from water after mixing • Differences between terms related to oil quality, such as pour point, neutralization number, and other lab test values

💭 Think About

• Think about which term is associated with oil and water separation in purification or centrifuge operations, not temperature behavior or acidity. • Ask yourself: which option refers to how stubborn or easy an oil-water mixture is to break apart, especially in fuel and lube oil treatment? • Consider what property engineers care about when they want water removed from oil in separators or settling tanks.

✅ Before You Answer

• Verify which choice is specifically tied to oil-water separation characteristics, not to corrosion/acid levels or low-temperature flow. • Eliminate any options that describe temperature-related properties, such as when an oil stops flowing. • Check which term is used when discussing emulsions and how quickly clear oil and clear water layers reform after mixing.