Hello, Mary,
Is the quesion written correctly?
3.8x10-2mol x 378g
0.0670mol
would give an answer with the unit mol*g. I wonder if the 378 is actual the molar mass of a compound of which we have 3.8x10-2mol.
When multiplied, we would have an answer in units of grams. It would be 14.4 grams
Bob