Tentukan masa molekul relatif dari k2cro7

Mr K2CrO7 = (2*ArK+1*ArCr+7*ArO)
=(2*39,098+1*52,941+7*16)
=(78,196+52,941+112)
=243.137 mol

Mr K2CrO7 = (Ar K x 2) + Ar Cr + (Ar O x 7)
= (39 x 2) + 52 + (16 x 7)
= 242