What is the name of the physical change that occurs in each of the following instan a. Oxygen is cooled from -150°C to -200°C. b. Iron is cooled from 1600°C to 1500°C. C. Mercury is heated from -130°C to -100°C. 9. Which colorless substance is a solid at -50°C?

10. Which substance is a liquid at 1000°C?

11. Which substance condenses from a gas to a liquid as the temperature is cooled 20°C to -50°C?