Help im stuck, will give the crown

How many moles are in 43.9 l of oxygen

Draw the aromatic compound toluene (methylbenzene). show all hydrogen atoms, including those on the ring.

6) (a) calculate the absorbance of the solution if its concentration is 0.0278 m and its molar extinction coefficient is 35.9 l/(mol cm). the depth of the cell is 5 mm. (b) what is the %t? (7) calculate the absorbance of the solution if the transmitted light intensity is 70% of the initial light beam intensity