According to Newton's Third Law, if a hammer puts a force of 200 N on a nail, how much force does the nail put back on the hammer? a. 200 N
b. -200 N
c. 50 N
d. 150 N

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles