An atom of 64ni has an experimentally determined nuclear mass of 63.9280 amu. calculate the mass defect, δm, in atomic mass units (amu).

You can determine the mass defect when you calculate for the absolute difference of the experimentally determined molar mass and the theoretical molar mass.

64Ni means there are 28 protons, 28 electrons and (64 - 28) = 36 neutrons. The mass of each proton is 1.0072766 amu; the mass of each electron is 0.00054 amu; the mass of each neutron is 1.008664 amu.

Theoretical molar mass = 28(1.0072766 amu) + 28(0.00054 amu) + 36(1.008664) = 64.5308 amu

Thus,
Mass defect = |63.9280 amu - 64.5308 amu| = 0.6028 amu

molarity of the KI solution = 0.04 mol/L

Explanation:

Molarity (M) is the concentration of a solution expressed as the number of moles of solute per liter of solution.  

The law that we can applied to calculate the M is:  

M = n / V

n - number of moles

V- volume of the solution (liters)

Then insert in the equation the values from the question;  

M = 0.082 mol  /  2.03 L = 0.04 mol/L