For strontium chloride, the light released when electrons transition between energy levels has a wavelength of 630 nm. Calculate: the wavelength in meters
the frequency in Hertz
the Energy in Joules

Idont know. if you want an answer you need to give us some context dude.

The surface of the water droplet is held together by the attraction between molecules. in order for water to flow more easily into these small spaces, you need to decrease its surface tension. you can do this by adding soap, which is a surfactant (a material that decreases the surface tension of a liquid).

Melting increases as mass increases. since alkanes are not branched molecular structures, the one with the heavier mass will have higher melting point.  octane's mp > butane's mp