Identify the phase transition occurring in each of the following. a. The water level in an aquarium tank falls continuously (the tank has no leak).
b. A mixture of scrambled eggs placed in a cold vacuum chamber slowly turns to a powdery solid.
c. Chlorine gas is passed into a very cold test tube where it turns to a yellow liquid.
d. When carbon dioxide gas under pressure exits from a small orifice, it turns to a white "snow."
e. Molten lava from a volcano cools and turns to solid rock.

At 300 mm hg, a gas has a volume of 380 l, what is the volume at standard pressure

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.

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.