In the reaction k2cro4 (aq) + pbcl2 (aq) 2kcl (aq) + pbcro4(s), how many grams of pbcro4 will precipitate out from the reaction between 25.0 milliliters of 3.0 m k2cro4 in an excess of pbcl2?

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