To find the mass from the given number of moles of the compound or molecule or atom.Use this formula
mass = moles x MM
where MM is the molar mass of the compound .To find the molar mass of CaCl2, consider the number of atoms of each element in the formula then multiply the number of elements with their atomic masses then finally add all the molecular weight.
CaCl2 has 1 Ca atom , 2 Cl atoms.
Ca = 1 x 40.07 = 40.07
Cl = 2 x 35.45 = 70.9
40.07 + 70.9 = 110.97 g / mol
mass = 0.89 x 110.97 = 98.76 g