Question

how many gram of NaNO3 are in 25cm3 of
0.01m NaNO3 solution?

Answer 1

Don't get too lazy in chemistry to use caps. 0.01m means 0.01 molal soln while 0.01M means 0.01 molar soln. I suspect you meant 0.01M. If so, then
mols = M x L = ?
Then grams = mols x molar mass