How many molecules are in 23g nitrogen dioxide gas, NO2 ? 

[ L= 6 x1023]

Name the element in group 17, period 2. (periodic table)

What does the mass of 0.7891 mol of ferric oxide (fe2o3)

Which of these is not an example of chemical weathering? a. iron-rich mineral rusting b. feldspar turning into clay c. limestone reacting with acid d. granite breaking up into sand