Temperature glide is the difference between the bubble and dew point.

• A. True
• B. False
• C. It is the difference between boiling point and freezing point
• D. It is the heat capacity change

Answer: (A)

Temperature glide is about how a mixture behaves during phase change. In zeotropic refrigerant blends, the liquid and vapor don’t have the same composition as they vaporize or condense, so the temperature at which boiling starts (the bubble point) and the temperature at which condensation starts (the dew point) at the same pressure aren’t the same. The difference between those two temperatures is called the temperature glide. For a pure substance, the bubble and dew points coincide, so there’s effectively no glide. The other options describe different concepts (boiling vs freezing points, or a change in heat capacity) and don’t capture the meaning of glide.