Which action characterized Earth's earliest atmosphere (atmosphere I) ? Helium and hydrogen gases escaped earth's gravity.

Increased oxygen allowed reptiles to thrive.

Heat energy was retained and water vapor condensed.

Ultraviolet light split water vapor into hydrogen and oxygen

Ascientist measures the speed of sound in a monatomic gas to be 449 m/s at 20∘c. what is the molar mass of this gas?

Two people each hold the end of a rope and create waves by moving their arms up and down. this wave is best classified as a transverse wave because a) both the rope particles and the wave are moving in the same direction. b) the wave is moving up and down as the particles of the rope move horizontally. c) the wave is moving horizontally as the particles of the rope move up and down. eliminate d) the wave is moving in a parallel direction with the motion of the person's arms.

An unsaturated hydrocarbon is a hydrogen-carbon compound with a. a network solid structure b. single bonds c. single bonds in a branched-chain structure d. double or triple bonds