Answer:
Mass = 2.65 g
Step-by-step explanation:
Given data:
Mass of sodium carbonate = ?
Mass of water = 0.125 g
Molality = 0.200 m
Solution:
Formula:
Molality = number of moles of solute / mass of solvent in Kg
by putting values,
0.200 m = Number of moles of solute / 0.125 kg
Number of moles = 0.200 m × 0.125 kg
Number of moles = 0.025 mol
Mass of sodium carbonate:
Mass = number of moles × molar mass
Mass = 0.025 mol × 106 g/mol
Mass = 2.65 g