Answer:
n=5
Explanation:
Applying the Rydberg's equation
hc/l= RH[(1/nf^2)-(1/ni^2)
Let l= wavelength= 3745×10^-9m
h=6.63×10^-34 , c= 3.0×10^8, RH= 2.179×10^-18
Substitute into the Rydberg's equation and simplify
(6.63×10^-34×3×10^8)/3745×10^-9=2.179×10^-18(1/nf^2 -1/8^2)
0.024= 1/nf^2 -0.0156
0.024+0.0156= 1/nf^2
0.0396= 1/nf^2
nf^2= 25.3
Take square root of both sides
nf= 5.02=5
Answer:
2.41 g of NaCl is needed
Explanation:
Molarity of solution = (Number of moles of solute)/(Volume of solution in Litre)
Here sodium chloride (NaCl) is solute in saline solution
275 mL = 0.275 L
So, number of moles of NaCl in 275 mL saline solution =
Molar mass of NaCl = 58.44 g/mol
Number of moles = (mass)/(molar mass)
So, mass of 0.04125 moles of NaCl =
So, 2.41 g of NaCl is needed
Answer:
evaporation or heating
Explanation:
this is the change from solid to liquid