Number of moles is defined as the mass of substance given in grams divided by the molar mass of substance.
It is given that mass of is 2.50 g and molar mass of is 134.45 g/mol.
Therefore, calculate number of moles as follows.
Number of moles of
= 0.0186 mol
= 0.019 mol (approx)
Thus, we can conclude that 2.50 g CuCl2 equals 0.019 moles (approx).