You need to know the energy frequency relationship for photons, which is thanks to Max Planck:
Photon Energy = Planck constant x Frequency
Rarranged:
Photon Energy / Planck Constant = Frequency
Planck Constant = 6.63x10^-34
2.93x10^-25 / 6.63x10^-34 = Frequency
Ethane is an alkane. Methane is also an alkane and is considered to be the simplest alkane. The difference is ethane has only 2 carbon. That carbon has 6 hydrogen attached to it. So what we do is we multiply the moles of ethane by the number of hydrogen (by dimension analysis) resulting to 82.68 moles H.
I believe it is B (CCl4) because it contains carbon
Answer : Hg (Mercury)
Explanation : In the given series of elements Na falls after the Cu in the reactivity series, for Pb it also falls after Cu, and for Mg it is the same.
Only Hg which is mercury can spontaneously donate its electrons to copper in the solution because it falls before Cu in the reactivity/activity series.
Anwser: 4:15
You add 45 minutes to 30 minutes which comes out to be 75 minutes, subtract that from 60 because there are only 60 minutes in an hour, which is 15.. so it's 4:15