What might cause matter to change states

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

Acar of mass m goes around a banked curve of radius r with speed v. if the road is frictionless due to ice, the car can still negotiate the curve if the horizontal component of the normal force on the car from the road is equal in magnitude to 101) a) mv2/r b) mg/2. d) mg e) tan[v2/(eg)]

Calculate the mass of an object that has a momentum of 100kg x m/sec and velocity of 4 m/sec