Complete combustion of 9.00 g of a hydrocarbon produced 28.9 g of co2 and 9.87 g of h2o. what is the empirical formula for the hydrocarbon?

The is a particle with one unit of positive charge a. proton b. positron c. electron d. nucleus awnser quick it is a important science test!

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.

Arectangle has a diagonal 20 inches long that forms angles of 60 and 30 with the sides. find the perimeter of the rectangle. for geometry