A certain element consists of two stable isotopes. The first has a mass of 121 amu and a percent natural abundance of 57.3 %. The second has a mass of 123 amu and a percent natural abundance of 42.8 %. What is the atomic weight of the element? amu

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.

#20 which type of bond is formed when bases pair in dna? ionic bond covalent bond coordinate bond hydrogen bond

How many moles of co2 are produced during the complete combustion of 3.6 moles of c2h6