The molecular weight, or molar mass, of Cd(NO3)2 is 236.418 grams/mole. This is found by multiplying the atomic mass of each constituent atom by the number of times it occurs and adding all the atomic masses together.
There is one cadmium atom in the compound with an atomic mass of 112.41. There are also two nitrogen atoms, each with an atomic mass of 14.007, and six oxygen atoms, each with an atomic mass of 15.999. The sum of 112.41 + 2(14.007) + 6(15.999) is 236.418. The mole is a unit of measurement defined as the amount of any substance that contains approximately 6.022 x 10^23 elementary particles, usually atoms or molecules.