Question

A single atom of platinum has a mass of 3.25 x 10-22g. What is the mass of 6.0 x 1023 platinum atoms?

Answer 1

Even though the numbers are in scientific notation, they are still just numbers. Essentially the question is as simple as "An apple weighs an ounce, how much do 35 apples weigh?". So all you have to do is multiply.

3.25 x $10^{-22}$   x  6.0 x$10^{23}$  = 195