A solution is made by mixing 20.0 mL of toluene C6H5CH3d=0867gmL with 140.0 mL of benzene C6H6d=0874gmL. Assuming that the volumes add upon mixing, the molarity (M) and molality (m) of the toluene are...

Question

A solution is made by mixing 20.0 mL of toluene C6H5CH3d=0867gmL with 140.0 mL of benzene C6H6d=0874gmL. Assuming that the volumes add upon mixing, the molarity (M) and molality (m) of the toluene are...

______ M and

______ m.

I need help. :(

Answer 1

1. Use:

mass = (volume)*(density), or
grams = (milliliters)(grams/ml)
to calculate the mass (grams) of each compound.
2. Find the molar mass of toluene.
3. Divide the mass (grams) of toluene by the molar mass of toluene to convert grams to moles.
4. Convert the grams of benzene to kilograms.
5. molality = (moles toluene)/(kgs of benzene)

Answer 2

To find the molarity,

1. Convert the 140 mLs of benzene to liters
2. Molarity = (moles of toluene) / (liters of benzene)

NOTE: This is a continuation of the previous answer (finding the molality). Refer to steps 2 and 3.

Answer 3

To find the molarity (M) and molality (m) of the toluene solution, we need to first calculate the number of moles of toluene. Here's how you can do it:

Step 1: Calculate the mass of toluene:
Mass of toluene = volume of toluene x density of toluene
= 20.0 mL x 0.867 g/mL
= 17.34 grams

Step 2: Calculate the number of moles of toluene:
Moles of toluene = mass of toluene / molar mass of toluene

The molar mass of toluene (C6H5CH3) can be calculated by adding up the atomic masses of its constituent elements:
Molar mass of toluene = (6 x atomic mass of carbon) + (5 x atomic mass of hydrogen) + (1 x atomic mass of toluene)
= (6 x 12.01 g/mol) + (5 x 1.01 g/mol) + (1 x 12.01 g/mol)
= 92.14 g/mol

Now, we can calculate the moles of toluene:
Moles of toluene = 17.34 g / 92.14 g/mol
= 0.1881 mol

Step 3: Calculate the volume of the solution:
Volume of the solution = volume of toluene + volume of benzene
= 20.0 mL + 140.0 mL
= 160.0 mL

Step 4: Calculate the molarity (M) of the toluene solution:
Molarity (M) = moles of toluene / volume of solution (in liters)
= 0.1881 mol / 0.160 L
= 1.175 M (rounded to three decimal places)

Step 5: Calculate the mass of the benzene:
Mass of benzene = volume of benzene x density of benzene
= 140.0 mL x 0.874 g/mL
= 122.36 grams

Step 6: Calculate the molality (m) of the toluene solution:
Molality (m) = moles of toluene / mass of solvent (in kg)
= 0.1881 mol / 0.12236 kg
= 1.537 m (rounded to three decimal places)

Therefore, the molarity (M) of the toluene solution is 1.175 M and the molality (m) is 1.537 m.