To find the mass of nickel, you need to (1) convert moles to grams (via atomic mass from the periodic table) and then (2) convert grams to nanograms. These ratios need to be multiplied by each other, starting with the given value. It is important to arrange the conversions/ratios in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 3 sig figs to reflect the given value (1.23).
Atomic Mass (Ni): 58.693 g/mol
1 gram = 1 x 10⁹ nanograms
1.23 moles Ni 58.693 g 1 x 10⁹ ng ---------------------- x ---------------------- x --------------------- = 7.22 x 10¹⁰ ng Ni 1 mole 1 g
