Question

Calculate the molality of a solution formed by adding 6.30 g NH4CL to 15.7 g of water

Answer 1

Answer:

Molality = 7.5 mol/kg

Explanation:

Given data:

Mass of NH₄Cl = 6.30 g

Mass of water = 15.7 g (15.7/1000 =0.016 kg)

Molality = ?

Solution:

Formula of molality:

Molality = Moles of solute / mass of solvent in gram

Now we will first calculate the number of moles of solute( NH₄Cl )

Number of moles = mass/ molar mass

Molar mass of  NH₄Cl = 53.491 g/mol

Number of moles = 6.30 g/  53.491 g/mol

Number of moles =  0.12 mol

Now we will calculate the molality.

Molality = Moles of solute / mass of solvent in gram

Molality =  0.12 mol / 0.016 kg

Molality = 7.5 m

or        (m=mol/kg)

Molality = 7.5 mol/kg

Answer 2

Quantification of moles of a solute in a solution of a kilogram of a solvent is called molality.

The correct answer is:

The molality of the NH₄Cl is 7.5 mol/kg

This can be calculated as:

• Quantity of NH₄Cl = 6.30 g

• Quantity of H₂O= 15.7 g

       $\dfrac{15.7}{1000}&= 0.016 \;\text{kg}$

Molality can be calculated by:

$\text{Molality} &= \dfrac{\text{Moles of solute}}{\text{Mass of solvent in kg or 1000 g}}$

To calculate the number of moles of solute ( NH₄Cl ):

$\text{Number of moles} & = \dfrac{\text{Mass}}{\text{Molar mass}}$

Molar mass of NH₄Cl = 53.491 g/mol

$\text{Number of moles} & = \dfrac{\text{6.30 g}}{\text{53.491 g/mol}} & = 0.12 \; \text{mol}$

Now, molality can be calculated:

$\text{Molality} &= \dfrac{\text{0.12 mol}}{\text{0.016 kg}}$

Molality = 7.5 m

Therefore, the Molality of solute of NH₄Cl = 7.5 mol/kg.

To learn more about molality refer to the link:

https://brainly.com/question/15490677