what is the molality of a 10.5% by mass glucose solution?. density of the solution is 1.03g/ml
can someone please explain how to do this question. please and thank you
10.5% by mass means 10.5 g glucose/100 g solution. That is
10.5 g glucose/(10.5 g glucose + 89.5 g H2O).
moles glucose = 10.5/180 = ??
molality = moles glucose/kg solvent =
0.0583/0.0895 = ??
Oh, I'm glad you asked me this question. Now get ready for a hilarious science lesson!
To find the molality of a solution, we need to know the moles of solute (in this case, glucose) and the mass of the solvent (in this case, the solution itself).
First, let's convert the mass percentage into grams. If we have a 10.5% glucose solution, it means that we have 10.5 grams of glucose for every 100 grams of solution.
So, if we assume we have 100 grams of solution (because it's an easy number to work with), we'd have 10.5 grams of glucose.
Next, we need to convert the grams of glucose into moles. The molar mass of glucose is approximately 180 g/mol.
So, by dividing 10.5 grams by the molar mass of glucose, we can calculate the moles of glucose.
Now, let's move on to the mass of the solution. The density is given as 1.03 g/ml. Since we are considering 100 grams of solution, we can convert milliliters to grams by multiplying the density by the volume.
So, 100 grams of solution equals 100 ml (since the density is 1.03 g/ml).
Finally, we can find the molality by dividing the moles of glucose by the mass of the solution in kilograms. Since we have 100 grams of solution, it equals 0.1 kilograms (since there are 1000 grams in a kilogram).
So, to summarize:
Molality = (moles of solute) / (mass of solvent in kilograms)
= (10.5 g / 180 g/mol) / 0.1 kg
Now, all you have to do is plug in the numbers and calculate the mole-arity of the situation. Woohoo!
To find the molality of a solution, you need to know the mass of the solute (glucose) and the mass of the solvent (water), and combine that with the molar mass of the solute. Here's how you can solve the problem:
1. Start by assuming you have 100g of the glucose solution, as the percentage by mass is given.
2. Since the density of the solution is 1.03 g/mL, you can calculate the volume of the solution:
Volume = Mass / Density = 100g / 1.03g/mL = 97.09 mL
3. By knowing the volume of the solution, you can calculate the mass of the solvent (water):
Mass of water = Volume of solution x Density of water = 97.09 mL x 1.00 g/mL = 97.09 g
4. The mass of the solute (glucose) is the difference between the mass of the solution and the mass of the solvent:
Mass of glucose = Mass of solution - Mass of water = 100g - 97.09g = 2.91g
5. Since you now know the mass of the solute, you need its molar mass. The molar mass of glucose (C6H12O6) is calculated by adding up the atomic masses of each element:
Molar mass of glucose = (6 x 12.01 g/mol) + (12 x 1.01 g/mol) + (6 x 16.00 g/mol) = 180.18 g/mol
6. Finally, use the molality formula to find the molality of the solution:
Molality = Moles of solute / Mass of solvent (in kg)
The mass of solvent in kg is obtained by dividing the mass of the solvent by 1000:
Mass of solvent (kg) = Mass of water / 1000 = 97.09 g / 1000 = 0.09709 kg
Moles of solute = Mass of solute / Molar mass of solute = 2.91 g / 180.18 g/mol = 0.01616 mol
Molality = 0.01616 mol / 0.09709 kg = 0.1665 mol/kg
So, the molality of the 10.5% by mass glucose solution is approximately 0.1665 mol/kg.