Answer:
0.875 moles solute
Step-by-step explanation:
You can find the moles of the solute using the molality ratio:
Molality = moles solute / mass (kg) solution
After converting the mass to kilograms, you can plug the values into the ratio and simplify to find the moles.
1,000 g = 1 kg
350 g 1 kg
-------------- x --------------- = 0.35 kg solution
1,000 g
Molality = moles solute / mass solution
2.5 m = moles solute / 0.35 kg
0.875 = moles solute