Which have different numbers of electrons?

How many molecules are present in 3 mols of silicon dioxide (sio2)?

What is the angular momentum of the bar about the axle?

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?