Respuesta :

Answer:

first.....lets calculate the molar mass of KClO4

39+35.5+16*4

39+35.5+64

=138.5g/mol

so that mean every mole have 138.5g...got that?

138.5g = 1mole

123g=x mole

123/138.5=x

x=0.888mol

Answer:

Number of moles = mass /molar mass

                              = 123 g/ 242.0111 g/mol

                                 = 0.508 mol

Explanation: