Question

Molality of 1.80 gram of kcl in 16.0 mol of H2o

Answer 1

Answer:

Explanation: Hope it helps

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Answer 2

Answer:

The molality of $1.80 gram$ of $KCl$ in $16.0 mol$ of $H_{2}O$ is $0.08 molal$.

Explanation:

Given,

The mass of the solute ($KCl$) = $1.80g$

The number of moles of the solvent ($H_{2}O$) = $16.0 mol$

The molality =?

As we know,

• Molality is the number of moles of solute per kilogram of the solvent.
• Molality = $\frac{Moles of solute}{Mass of solvent(Kg)}$    -------equation(1)

Firstly, we have to find out the mass of the solvent.

As we know,

• The molar mass of $H_{2}O$ = $18g/mol$.

As given,

• The number of moles of $H_{2}O$ = $16.0mol$

Now,

• Number of moles of solvent = $\frac{Mass of H_{2}O }{Molar mass of H_{2}O }$
• $16 = \frac{Mass of H_{2}O }{18}$
• Mass of the solvent ( $H_{2}O$ ) = $288g$ = $0.288Kg$.

Now, we have to find out the number of moles of the solute ($KCl$).

As we know,

• The molar mass of $KCl$ = $74.55g/mol$.
• The mass of the solvent ($KCl$) = $1.80g$

Therefore,

• Number of moles of solute = $\frac{Mass of KCl }{Molar mass of KCl }$
• Number of moles of solute ( $KCl$ ) = $\frac{1.80}{74.55}$ = $0.024 mol$

Now, after putting all the values in the given equation, we get:

• Molality = $\frac{Moles of solute}{Mass of solvent(Kg)}$
• Molality = $\frac{0.024}{0.288}$ = $0.08 molal$

Hence, the molality = $0.08 molal$.