Speed = frequency x wavelength
So rearrange the formula: wavelength= speed/ frequency
wavelength = (2.998 x 108) ÷ (5.10 x 1014)
Answer:
(a) 
(b) 
(c) 
Explanation:
Hello,
In this case, given the molality in mol/L, we can compute the required units of concentration assuming a 1-L solution of acetonitrile and lithium bromide that has 1.80 moles of lithium bromide:
(a) For the molality, we first compute the grams of lithium bromide in 1.80 moles by using its molar mass:

Next, we compute the mass of the solution:

Then, the mass of the solvent (acetonitrile) in kg:

Finally, the molality:

(b) For the mole fraction, we first compute the moles of solvent (acetonitrile):

Then, the mole fraction of lithium bromide:

(c) Finally, the mass percentage with the previously computed masses:

Regards.
Answer:
Today, the average total production cost of “standard modulus” carbon fiber is in the range of $7-9 per pound.
Every orbital in a subshell is singly occupied with one electron before anyone orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin.