Who earned a nobel peace prize for their study of the photoelectric effect?

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.

Describe the properties of sodium, chlorine, and sodium chloride

Select the statement that describe chemical properties a. antacid tablets neutralize stomach acid b. helium is the lightest monatomic element c. water freezes at 0 celsius d. mercury is liquid at room temperature