CHem Mole Calculations, Help~

1) Calculate the number of moles needed for making this particular concentration:
mole = conc x vol/1000
mole = 0.5 x 100/1000
here i am taking 100g = 1000ml
mole = 0.05 mole
2) the molar mass of the compound is given to be 281.1g, as 0.05 mole is needed, this is just multiply the mole calculated moles with the given molar mass to give:
mass needed = 0.05*281.1
mass needed = 14.055g = 14.1g (corr. to 3 sig. fig)