Question

The formula weight of calcium nitrate (ca(no3)2), rounded to one decimal place, is ________ amu. the formula weight of calcium nitrate (ca(no3)2), rounded to one decimal place, is ________ amu. 204.2 150.1 116.1 164.0 102.1

Answer 1

164.0 First we must look up the atomic weight of all elements in calcium nitrate Ca: 40.078 N: 14.0067 O: 15.999 Then we compute the mass of the nitrate polyatomic ion which contains one nitrogen and 3 oxygen atoms. 14.0067+3*15.999 = 62.0037 For the entire molecule we calculate the weight of two nitrates and one calcium 2 * 62.0037 + 40.078 = 164.0152 rounding to the tenths place results in 164.0