What is the molality of KBr in a solution made by dissolving 2.21 g of KBr in 897g of water

moles KBr = grams/molar mass.

m = moles/kg solvent = moles/0.897 = ?

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To determine the molality of KBr in the given solution, you first need to understand the concept of molality.

Molality (m) is a measure of the concentration of a solute in a solution, and it is defined as the number of moles of solute per kilogram of solvent. The formula for molality is:

molality (m) = moles of solute / mass of solvent (in kg)

To find the molality of KBr in the solution, follow these steps:

Step 1: Calculate the moles of KBr.
- The molar mass of KBr is obtained by summing the atomic masses of potassium (K) and bromine (Br):
Molar mass (KBr) = atomic mass (K) + atomic mass (Br)
- Look up the atomic masses of potassium and bromine from the periodic table.
- Calculate the molar mass of KBr.
- Use the formula: moles = mass / molar mass to calculate the moles of KBr.

Step 2: Convert the mass of water to kilograms.
- The given mass of water is in grams, and it needs to be converted to kilograms.
- Divide the mass of water by 1000 to convert it to kilograms.

Step 3: Calculate the molality.
- Use the formula: molality (m) = moles of KBr / mass of water (in kg).

Let's apply these steps to the given values:

Step 1:
- Molar mass (KBr) = atomic mass (K) + atomic mass (Br)
- Look up the atomic masses of potassium (K) and bromine (Br): atomic mass (K) = 39.10 g/mol, atomic mass (Br) = 79.90 g/mol.
- Calculate the molar mass of KBr: Molar mass (KBr) = 39.10 + 79.90 g/mol.
- Calculate the moles: moles = mass / molar mass = 2.21 g / (39.10 + 79.90) g/mol.

Step 2:
- Convert the mass of water to kilograms: mass of water in kg = 897 g / 1000.

Step 3:
- Calculate the molality: molality (m) = moles of KBr / mass of water (in kg).

By following these steps, you can calculate the molality of KBr in the given solution.