Calculate Mass of Paradichlorobenzene for .05 Molal Solution

In summary, the mass of paradichlorobenzene for a 0.05 molal solution can be calculated using the formula mass = moles x molar mass. Molality is a measure of concentration that takes into account the mass of the solvent, and can be converted to molarity by dividing by the density of the solution. The molar mass of paradichlorobenzene is 147.01 g/mol. The mass of paradichlorobenzene will change with different molalities, as it is directly proportional to the molality.
  • #1
babbagee
74
0
Calculate the mass of paradichlorobenzene (M=147.01g/mol) that should be added to 20.00 ml of cyclohexane (d = .779g/ml) to make a .05 molal solution.

I did this problem but i don't know if i did it correctly.
first i found the mass of cyclohexane by using m=dv.

(.05moles solute/kg solvent)(15.58g)(1kg/1000g)(147.01g/mol) = .11g

does this seem correct. I am not sure.

Thanks.
 
Chemistry news on Phys.org
  • #2
That's what I got...
 
  • #3


The calculation you have done seems to be correct. To confirm, we can use the formula for molality (m) which is moles of solute (n) divided by mass of solvent (m) in kilograms.

m = n/m

Given that the molality (m) is 0.05 molal and the mass of solvent (m) is 20.00 ml of cyclohexane, we can rearrange the formula to solve for the mass of solute (n).

n = m x m

n = (0.05 molal) x (20.00 ml/1000g) x (0.779 g/ml) = 0.0779 g

This is very close to the value you have calculated, so your answer seems to be correct. Keep in mind that there may be slight variations due to rounding off of numbers.
 

1. How do you calculate the mass of paradichlorobenzene for a 0.05 molal solution?

The mass of paradichlorobenzene for a 0.05 molal solution can be calculated using the formula mass = moles x molar mass. First, determine the number of moles of paradichlorobenzene in the solution by multiplying the molality (0.05 mol/kg) by the mass of the solvent (in kg). Then, multiply the number of moles by the molar mass of paradichlorobenzene (147.01 g/mol) to get the mass in grams.

2. What is the definition of molality?

Molality is a measure of the concentration of a solution, expressed as the number of moles of solute per kilogram of solvent. It is different from molarity, which is expressed as the number of moles of solute per liter of solution. Molality takes into account the mass of the solvent, making it a more accurate measure of concentration for solutions that may have significant changes in volume upon dissolution.

3. How do you convert molality to molarity?

To convert molality to molarity, you need to know the density of the solution. Once you have the density (in g/mL), divide the molality (mol/kg) by the density (g/mL) to get the molarity (mol/L).

4. What is the molar mass of paradichlorobenzene?

The molar mass of paradichlorobenzene is 147.01 g/mol. This can be found by adding together the atomic masses of the elements present in the compound (C6H4Cl2), which are carbon (12.01 g/mol), hydrogen (1.01 g/mol), and chlorine (35.45 g/mol).

5. How does the mass of paradichlorobenzene change with different molalities?

The mass of paradichlorobenzene will change with different molalities because it is directly proportional to the molality. As the molality increases, the mass of the paradichlorobenzene will also increase. This is because more moles of the solute are present in the solution, which requires a larger mass of the solute to maintain the same molality.

Similar threads

Iodine Adsorption and Titration with Na2S2O3
    • Chemistry
Replies
4
Views
2K
Chemistry Exercise about an aqueous solution (containing a halogen)
    • Biology and Chemistry Homework Help
Replies
6
Views
2K
Molality calculation.... Is it correct?
    • Biology and Chemistry Homework Help
Replies
12
Views
7K
Calculating time to reduce alcohol in wine using heating method
    • Chemistry
4
Replies
131
Views
4K
What is the molality of 1M NH4OH in 70.092ml of water?
    • Biology and Chemistry Homework Help
Replies
10
Views
3K
A problem in volumetric calculations in Chemistry
    • Biology and Chemistry Homework Help
Replies
2
Views
2K
MeOH:H2O Freezing Point Depression Calculation Issue
    • Chemistry
Replies
1
Views
2K
Chemistry Moles of NaOH to Create Buffer Solution pH=6 in 0.42M Ethanoic Acid
    • Biology and Chemistry Homework Help
Replies
3
Views
1K
Comparing Molality & Molarity: Which is More Concentrated?
    • Chemistry
Replies
2
Views
5K
Increasing the concentration of a solution - Diff Eq?
    • Chemistry
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top