How many moles of NaCl is in 500 ml of 0.260 M NaCl?How many grams of NaCl is this?

well first of all your formula is n=m/M
n=number of moles
m=mass of substance
M=molar mass

You need to find the mass number of the compound.

Molarity = moles of substance/Liters of solution ( convert mL to L )

If you have moles you can get mass.

130g molarity=m\ml m=ml*molarilty