yes, this would be cheating, but.........
"Refer to the periodic table and calculate the molecular weights for the compounds PH3 and SO2 (est. 34 and 64 respectively). Then determine how many grams of PH3 contain the same number of molecules as 6.41g of SO2."
"Refer to the periodic table and calculate the molecular weights for the compounds PH3 and SO2 (est. 34 and 64 respectively). Then determine how many grams of PH3 contain the same number of molecules as 6.41g of SO2."