A solution is made by mixing 90.6 g of magnesium sulfate heptahydrate with 2320.0 g of water.

690.00 mL of the solution has a mass of 745.20 g.

1. What is the molarity of the magnesium sulfate solution?

2. What is the molarity of the magnesium ion?

3. What is the molality of the magnesium sulfate solution?

See your post bedlow for #1.

2. MgSO4.7H2O has 1 mol Mg for each mols MgSO4.7H2O; therefore, M mg^+ = M MgSO4.7H2O

3. m = mols MgSO4.7H2O/kg solvent.
Post your work if you get stuck.

The post that I followed for #1 ended up with the wrong answer

Let me look at how you arrived at the answer.

To find the molarity of the magnesium sulfate solution, we need to calculate the number of moles of magnesium sulfate and then divide it by the volume of the solution in liters.

1. Molarity of Magnesium Sulfate Solution:
Step 1: Convert the mass of magnesium sulfate heptahydrate to moles. First, we need to determine the molar mass of magnesium sulfate heptahydrate. The molar mass of each component is as follows:
- Magnesium (Mg): 24.31 g/mol
- Sulfur (S): 32.07 g/mol
- Oxygen (O): 16.00 g/mol
- Hydrogen (H): 1.01 g/mol
- Water (H2O): 18.02 g/mol

Since magnesium sulfate heptahydrate has seven water molecules attached, we multiply the molar mass of water by 7:
MgSO4 · 7H2O = (24.31 + 32.07 + (4 × 16.00)) + (7 × 18.02) = 246.48 g/mol

To calculate the moles of magnesium sulfate heptahydrate:
moles = mass / molar mass = 90.6 g / 246.48 g/mol = 0.3675 mol

Step 2: Convert the volume of the solution from milliliters (mL) to liters (L).
Since 1 L is equal to 1000 mL, the volume of the solution in liters is:
volume = 690.00 mL / 1000 = 0.690 L

Step 3: Calculate the molarity of the magnesium sulfate solution.
Molarity (M) = moles / volume = 0.3675 mol / 0.690 L ≈ 0.532 M

Therefore, the molarity of the magnesium sulfate solution is approximately 0.532 M.

To find the molarity of the magnesium ion, we need to consider that magnesium sulfate dissociates into magnesium ions (Mg2+) and sulfate ions (SO4²⁻) in solution. Since each formula unit of magnesium sulfate produces one magnesium ion, the molar concentration is the same.

2. Molarity of Magnesium Ion:
The molarity of the magnesium ion is approximately 0.532 M.

To find the molality of the magnesium sulfate solution, we need to calculate the moles of solute (magnesium sulfate) and then divide it by the mass of the solvent (water) in kilograms.

3. Molality of Magnesium Sulfate Solution:
Step 1: Calculate moles of magnesium sulfate heptahydrate as done above: 0.3675 mol.

Step 2: Convert the mass of water to kilograms.
mass = 2320.0 g = 2.320 kg

Step 3: Calculate the molality of the magnesium sulfate solution.
Molality (m) = moles / mass of solvent (kg) = 0.3675 mol / 2.320 kg ≈ 0.158 mol/kg

Therefore, the molality of the magnesium sulfate solution is approximately 0.158 mol/kg.