How many grams of CaCl2 are needed to make 100ml of a 15% solution in water if only the dihydrated (CaCl2 •2H20) salt is available?
You need to re-read the problem and see how impossible it is; however, I think I know what you are asking. You want a 15% solution of CaCl2 but you must use CaCl2.2H2O to make the solution. If that's what you're asking, do it this way. And I'm assuming that is 15 mass percent.
For 15% CaCl2 you want 15 g CaCl2 in 100 g solution.
15 g CaCl2 x (molar mass CaCl2.2H2O/molar mass CaCl2) = grams CaCl2.2H2O needed.
Dissolve that many g CaCl2.2H2O in a little water and add H2O to make a total of 100 g solution.
I'm just as perplexed. Thank you for the help
To calculate the mass of CaCl2 required to make a 15% solution in water, you need to consider the molar mass of CaCl2 and the density of the dihydrated salt available.
Here's how you can calculate it:
1. Determine the molar mass of CaCl2:
- Calcium (Ca) has an atomic mass of 40.08 g/mol
- Chlorine (Cl) has an atomic mass of 35.45 g/mol (since there are two chlorine atoms, multiply by 2)
- So, the molar mass of CaCl2 is (40.08 + 2 * 35.45) g/mol = 110.98 g/mol
2. Convert the given volume (100 ml) to grams. Since the density of water is approximately 1 g/ml, the volume of the 15% solution will be equal to its mass.
- 100 ml = 100 g
3. Calculate the amount of CaCl2 needed:
- Since the solution is 15% CaCl2, this means that 100 g of the solution contains 15 g of CaCl2.
- To find the mass of CaCl2 needed to make a 15% solution, use the following equation:
Mass of CaCl2 = (Desired percentage / 100) * Mass of the solution
- Substitute the values:
Mass of CaCl2 = (15 / 100) * 100 g = 15 g
Therefore, you would need 15 grams of CaCl2 to make 100 ml of a 15% solution in water using the dihydrated form (CaCl2 • 2H2O) of the salt.