A solution is prepared by dissolving 15.8 g of MgCl2 in 255 g of water. What is the mole fraction of MgCl2 in this solution?

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.

Draw the lewis structure for the trisulfur s3 molecule. be sure to include all resonance structures that satisfy the octet rule.

What is a main difference between a mixture and a pure substance? a mixture is only a liquid, but a pure substance can be in any state. a mixture looks the same throughout, but a pure substance does not.1 a mixture can vary in composition, but a pure substance has a set composlo a mixture can be made up of a single compound, but a pure substance car