Question

What is the molarity of a 5.39 m solution of benzene (c 6 ​ h 6 ​ ) dissolved in toluene (c 7 ​ h 8 ​ ), given that the solution has a density of 0.869 g/ml?

Answer 1

To calculate the molarity of the 5.39 M solution of benzene dissolved in toluene, we can use the formula Molarity = Moles / Volume. We need to determine the number of moles of benzene in 1 L of the solution. Given the density of the solution, 0.869 g/ml, we can calculate the mass of 1 L of the solution and then use the molar mass of benzene to find the moles. Finally, we divide the moles by the volume to find the molarity.

Step-by-step explanation:

To calculate the molarity of the benzene solution, we first need to determine the number of moles of benzene in it. We can use the formula:

Moles = Mass (g) / Molar Mass (g/mol)

Given that the density of the solution is 0.869 g/ml, we can calculate the mass of 1 L (1000 ml) of the solution as:

Mass = 0.869 g/ml * 1000 ml = 869 g

Next, we need to find the molar mass of benzene, which is C6H6. The molar mass of carbon (C) is 12.01 g/mol and the molar mass of hydrogen (H) is 1.008 g/mol, so: Molar Mass = 12.01 g/mol * 6 + 1.008 g/mol * 6 = 78.11 g/mol

Now we can calculate the moles of benzene in the solution: Moles = 869 g / 78.11 g/mol = 11.12 mol

Finally, we can calculate the molarity using the formula: Molarity = Moles / Volume (L)

Given that the volume of the solution is 1 L, the molarity is: Molarity = 11.12 mol / 1 L = 11.12 M

Answer 2

The formula used to determine the molarity is:

`molarity = (number of moles of solute)/(volume of solution in Liter)` -(1)

Molality =
`5.39 m` (given)

As, molality =
`(number of moles of solute)/(mass of solvent in kg)`

That means 5.39 moles of solute are present in 1000 g of solvent.

Moles of solute, benzene = 5.39 moles.

Molar mass of benzene,
`C_6H_6 = 6* 12+6* 1 = 78 g/mol`

Using,
`number of moles = (mass of compound)/(Molar mass of compound)` we can determine the mass of benzene as:

`mass of benzene = number of moles of benzene * Molar mass of benzene`

`mass of benzene = 5.39 mol* 78 g/mol = 420.42 g`

Mass of solvent = 1000 g

Mass of solution = mass of solute + mass of solvent

Mass of solution =
`1000 g + 420.42 g = 1420.42 g`

Density of solution =
`0.869 g/mL` (given)

Since,
`density = (mass)/(volume)`

So, Volume of solution =
`(1420.42 g)/(0.869 g/mL)` =
`1634.54 mL`

Since,
`1 mL = 0.001 L`

So, volume of solution =
`1.634 L`

Substituting the values in formula (1):

`molarity = (5.39 mol)/(1.634 L) = 3.29 mol/L`

Hence, the molarity of the solution is
`3.29 M`.