Christian K. answered • 06/22/21
Master's in Chemistry - High school chemistry teacher
I see you've posted many similar questions, so I'll answer one so that you are able to answer the rest on your own.
When converting from grams to moles or moles to grams, we need to calculate the molar mass. We can do this by looking at the chemical formula and a periodic table.
Calcium Nitrate = Ca(NO3)2
1 Ca = 40.078 g/mol
2 N = 2 x 14.007 g/mol
6 O = 6 x 15.999 g/mol
1 Ca(NO3)2 = 164.086 g/mol
This means every 1 mole of calcium nitrate has a mass of 164.086 grams. Thus, we can simply divide the 0.500 g you were given in the problem by the molar mass of calcium nitrate to calculate the number of moles.
0.500 g / 164.086g/mol = 0.00305 mol (3 sig figs)
