The mass of one mole of KBr is the molar mass.
The molar mass is the sum of the atomic masses of each atom times the number of moles of atoms in the formula
So, molar mass of KBr is atomic mass of K * 1 + atomic mass of Br * 1
Atomic mass of K = 39.1 g/mol
Atomic mass of Br = 79.9 g /mol
=> molar mass of KBr = 39.1 g/mol + 79.9 g/mol = 119 g/mol
=> mass ot two moles of KBr = 2 moles * 119 g/mol = 238 g
Answer: 238 g