Question

Part 1: Each molecule of NO2, nitrogen dioxide, consists of 1 atom of N and 2 atoms of O. If you have 0.155 g. of NO2, how many molecules of NO2 do you have ?

0.155gx46.0 = moles
moles x 6.02 E23 = answer

Part 1 Answer: 2030000000000000000000

Part 2: How many atoms of N do you have ?
3 total parts, 1 part is N
So take first answer x 1

Part 2 Answer: 2030000000000000000000

Part 3: How many atoms of O do you have?
3 total parts, 2 parts are O
So take first answer x 2

Part 3: 4060000000000000000000

Part 4: What is the % by mass of N?

Part 5: What is the % by mass of O?

I need help on Part 4 & 5, but you'll need the previous information to do the problem. Thank you if you can help.

Answer 1

Solved, Nevermind.

Answer 2

See my note at your original post about the number of significant figures.
Also, in this post note the typo on the first problem. moles = 0.155/46.0 and not 0.155 x 46.0