Suppose that three unknown pure substances are liquids at room temperature. You determine that the boiling pint of substance A is 53 °C, that of substance B is 117 °C, and that of substance C is 77 °C. based on this information, rank the three substances in order of their vapor pressures at room temperature. Top label: Lowest vapor pressure at room temperatureLowest vapor pressure at room temperature

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.