Please help :) A compound has the empirical formula C2H3O and a molecular mass of 172 mol. What is its molecular formula?
a. C11H10 05
b. C6H9O3
c. C8H12O4
d. C4H6O2

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.

What physical property of gold makes panning a useful way to get gold from streams?

Which of the following statements is true about both nuclear fusion and nuclear fission? they occur in the sun. heavy atoms are split. two light nuclei combine. some mass changes into energy.