Prepare 250mL of 2.00%(w/v) CuSO4 from CuSO4x5H2O
I worked this for someone just a second ago. If not for you, I can try to find it and link it here.
thanks!!!! I realized i could get M from % and then followed the rest of your answer.
http://www.jiskha.com/display.cgi?id=1291601388
To prepare 250 mL of a 2.00% (w/v) CuSO4 solution from CuSO4·5H2O, you would need to take the following steps:
Step 1: Determine the molar mass of CuSO4·5H2O
CuSO4·5H2O is a hydrated compound, which means it contains water molecules (H2O) in addition to the CuSO4 molecules. To calculate the molar mass, you need to sum up the atomic masses of all the atoms present in the compound.
The atomic masses are as follows:
- Atomic mass of Cu = 63.55 g/mol
- Atomic mass of S = 32.07 g/mol
- Atomic mass of O = 16.00 g/mol
- Atomic mass of H = 1.008 g/mol
Thus, the molar mass of CuSO4·5H2O can be calculated as:
(63.55 g/mol Cu) + (32.07 g/mol S) + (4 × 16.00 g/mol O) + (5 × (2 × 1.008 g/mol H))
= 63.55 g/mol + 32.07 g/mol + 64.00 g/mol + 10.08 g/mol
= 169.70 g/mol
Step 2: Calculate the mass of CuSO4·5H2O needed
To prepare a 2.00% (w/v) solution, you need to know the mass of CuSO4·5H2O required to make up 2.00 grams in a total volume of 100 mL (0.100 L). The mass can be calculated using the following formula:
Mass (g) = (desired concentration % / 100) × volume (L) × molar mass (g/mol)
Substituting the given values:
Mass (g) = (2.00% / 100) × 0.100 L × 169.70 g/mol
Mass (g) = 0.020 g × 0.100 L × 169.70 g/mol
Mass (g) = 0.3394 g
So, you need 0.3394 grams of CuSO4·5H2O
Step 3: Prepare the solution
To prepare the 250 mL (0.250 L) solution, you would follow these steps:
- Weigh out 0.3394 grams of CuSO4·5H2O accurately using a balance.
- Dissolve the weighed CuSO4·5H2O in a suitable container by adding a small volume of distilled water and stirring until it is fully dissolved.
- Once fully dissolved, transfer the solution to a 250 mL volumetric flask.
- Add distilled water to the flask until the volume reaches the 250 mL mark, ensuring the bottom of the meniscus lies on the mark.
- Mix the solution thoroughly by inverting the flask a few times or using a stirrer.
Now, you have successfully prepared 250 mL of a 2.00% (w/v) CuSO4 solution from CuSO4·5H2O.