Which definition is correct? a) a physical change creates a new substance because bonds are broken or formed b) a chemical change occurs when the substance remains the same but the shape, or other physical characteristics change c) a physical change can happen without changing any characteristics of the substance d) a chemical change produces a new substance by breaking and forming new bonds

Answer from each drop-down menu. e characteristics of a borane molecule (bh). the lewis structure and table of electronegativities are given olecular shape is and the molecule is reset next erved. search e a

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 of the following are correct values for the ideal gas laws constant r