Combustion of gasoline in automobiles produces poisonous gases. catalytic converters that contain solid platinum, palladium, and rhodium change these poisonous gases into harmless gases. which statement describes the catalyst?
it is a homogeneous catalyst.
it provides an alternative pathway for the reaction.
it combines with poisonous gases to make them harmless.
it increases the energy that is needed for the reaction to occur.

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.

Identify the lewis base in this balanced equation: fe3+ h2o fe(h2o)63+

What is the difference between covalent bonds and ionic bonds? covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms. covalent bonds involve the transfer of electrons between charged atoms; ionic bonds involve the sharing of electrons between atoms. covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms. covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between charged atoms.