What is the mass of 0.0065 mole of ruthenium

6.5 mol Ru x101.07g Ru/1mol Ru = 0.656g Ru
Or is it 0.66g Ru

How did you multiply 6 x 100 and get less than 600 something?

6.5 x 101.07 I have as 656.955. You are allowed two sig figures so you round that to 660 but should be written as 6.6E2.