Giving 98 points which statement about enthalpy is true? a.)the enthalpy of formation for a pure element in its standard state is always positive. b.)the enthalpy of formation for a pure element in its standard state is always negative. c.)enthalpy is a state function because its change depends only on initial and final conditions. d.)enthalpy is not a state function because its change depends on the identities of the reactants and products.

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.