A 0.386g sample of a protein was dissolved in water and made up to a volume of 60mL at 21.0°C. At this temperature the osmotic pressure of this solution was 1.24mmHg. Calculate the molecular mass of the protein
12682 g mol-1
95025 g mol-1
9627613 g mol-1
5706 g mol-1
125.17 g mol-1
I just want to confirm my working
1.24mmHg/760torr= 0.00163atm
21+273= 294K
0.00163= C*0.08206*294
C= 0.0000676M
moles= 0.0000676*0.06L= 0.00000405
mass= 0.386g/0.00000405mol
= 9.5*10^4g/mol
That looks good to me. Good work.
Your working and calculation are correct. The molecular mass of the protein is approximately 9.5*10^4 g/mol, which corresponds to 95025 g/mol. Therefore, the correct answer is 95025 g/mol.
Your working is correct. Here is a step-by-step explanation of how to calculate the molecular mass of the protein:
1. Convert the osmotic pressure from mmHg to atm:
1.24 mmHg / 760 torr = 0.00163 atm.
2. Convert the temperature from °C to Kelvin:
21.0°C + 273 = 294 K.
3. Use the ideal gas law formula to calculate the concentration (C) of the protein solution:
C = (osmotic pressure) / (gas constant * temperature).
C = 0.00163 atm / (0.08206 L·atm/(mol·K) * 294 K).
C ≈ 0.0000676 M.
4. Calculate the number of moles of protein:
Moles = concentration (C) * volume.
Moles = 0.0000676 M * 0.06 L.
Moles ≈ 0.00000405 mol.
5. Calculate the molecular mass of the protein:
Mass = mass of protein / moles of protein.
Mass = 0.386 g / 0.00000405 mol.
Mass ≈ 9.5 * 10^4 g/mol.
So, the calculated molecular mass of the protein is approximately 9.5 * 10^4 g/mol.