Calculations with the unit cell of cesium chloride

A monocristal of CsCl weighs 260 g. Immersed in a beaker filled to the brim with petrol, it causes overflow of 65.5 cm3 liquid. Calculate (answers at the bottom):   - the molar mass of CsCl.   - the mass density of CsCl.   - the molar volume of CsCl.   - the number of cations (or anions) per unit cell.   - the number of unit cells per mole.   - the volume $V$ of one unit cell.   - the length of the edge $a$ of one unit cell.