Final answer:
While the exact solubility of ammonium bromide at 80°C isn't provided, the discussion focused on calculating molality and mole fraction for a solution using ammonia as an example.
Step-by-step explanation:
The question provided does not give the solubility data of ammonium bromide at 80°C directly. However, we can discuss the concepts involved in solubility and determine the molality and mole fraction for a similar compound, ammonia (NH3), in water. To calculate the molality of a solution that contains 0.850 g of ammonia in 125 g of water, we first need to convert grams of ammonia to moles by using the molar mass of ammonia (17.03 g/mol). Next, we divide the moles of ammonia by the kilograms of water to calculate the molality. To find the mole fraction of ammonia, divide the moles of ammonia by the total moles of both ammonia and water in the solution.