If we use a common alkyl halide, such as methyl bromide, and a common solvent, ethanol, we can examine the rate at which various nucleophiles substitute the methyl carbon. Nucleophilicity is thereby related to the relative rate of substitution reactions at the halogen-bearing carbon atom of the reference alkyl halide.
U.S. Navy. For an airplane to break the sound barrier, it must hit speeds of about 770 mph â when it does that a couple of things happen. All the air in front of the craft gets pushed together, can't get out of its own way â and when that magic number gets hit â the air finally breaks free and crashes behind the plane causing a sonic boom.
Chuck Yeager and the X-1 research plane that broke the sound barrier in 1947. It can be seen today at the Smithsonian Air & Space Museum in Washington, D.C. The speed of sound varies depending on the temperature of the air through which the sound moves. On Earth, the speed of sound at sea level â assuming an air temperature of 59 degrees Fahrenheit (15 degrees Celsius) â is 761.2 mph (1,225 km/h). Because gas molecules move more slowly at colder temperatures, that slows the speed of sound; sound moves faster through warmer air.