Carry out each of the following calculations, paying special attention to significant figures, rounding, and units (J = joule, the SI unit of energy; mol = mole, the SI unit for amount of substance):...

Carry out each of the following calculations, paying special attention to significant figures, rounding, and units (J = joule, the SI unit of energy; mol = mole, the SI unit for amount of substance):
a. (6.626X 10-34 J · s)(2.9979 X 108 m/s)

489 X 1 0 -9 m

b. (6.022 X 1 023 molecules/mol)( 1 .l 9 X 1 02 g)

46.07 glmol