Acetaldehyde is a substance commonly used in chemical factories. It is often produced by combining ethylene gas and oxygen gas.
Consider the following reaction:
12 molecules of ethylene (CH) react with 6 molecules of oxygen (O2) to produce some
amount of acetaldehyde (C, H,O).
Complete the table below.
Chemical element Number of atoms in the reaction
H
С
o
During this reaction, how many molecules of acetaldehyde (C2H,0) are produced?

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.