Answer: v = 2π2 Kme2 Z / nh
Explanation:
The formula for velocity of an electron in the nth orbit is given as,
v = 2π2 Kme2 Z / nh
v = velocity
K = 1/(4πε0)
m= mass of an electron
e = Charge on an electron
Z= atomic number
h= Planck’s constant
n is a positive integer.
<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles. We calculate as follows:
0.340 mol Br2 ( </span>6.022 x 10^23 molecules / mol ) = 2.05 x 10^23 molecules
Answer: 
Explanation:
Depression in freezing point is given by:
= Depression in freezing point
i= vant hoff factor = 1 (for non electrolyte like urea)
= freezing point constant = 
m= molality
Weight of solvent (X)= 950 g = 0.95 kg
Molar mass of non electrolyte (urea) = 60.06 g/mol
Mass of non electrolyte (urea) added = ?
Thus urea was dissolved.
It would be a physical change. It’s still water just in a different physical form. If it was a chemical change, it would no longer be water. For example, when the ice melts back into water...it’s still water.
