How many moles of Cacl are needed to be dissolved in .500g of H2O to form a 1.5m solution?

First, calcium chloride is CaCl2.

Second, 0.500 g is not very much H2O to be using to prepare any kine of solution. Check your problem and your post.

You want 1.5 m solution. The definition is
m = mols/kg solvent
1.5m=moles/kg. I don't know if that is 0.5 grams or 0.5 kg. You substitute whatever goes there.
Solve for moles, then substitute into the following:
moles = grams/molar mass and calculate grams.

To determine the number of moles of CaCl₂ needed to form a 1.5m solution, you need to know the molar mass of CaCl₂ and the formula for molarity.

Here's how you can solve it step by step:

Step 1: Find the molar mass of CaCl₂.
The molar mass of CaCl₂ can be calculated by adding up the atomic masses of its elements. The atomic mass of Ca is 40.08 g/mol, and the atomic mass of Cl is 35.45 g/mol.
Molar mass of CaCl₂ = (1 * Ca) + (2 * Cl) = 40.08 + (2 * 35.45) = 110.99 g/mol.

Step 2: Calculate the amount of CaCl₂ in moles.
To find the number of moles, use the equation:
Moles = Mass / Molar mass.
Given that the mass is 0.500 g and the molar mass is 110.99 g/mol:
Moles = 0.500 g / 110.99 g/mol.

Step 3: Calculate the molarity (M) of the solution.
The formula for molarity is:
Molarity = Moles of solute / Volume of solution (in liters).
Given that you want a 1.5m solution, the molarity is 1.5 mol/L and the volume is not provided.

If the volume of the solution is known, you can calculate the moles of CaCl₂ required using the formula:
Moles of CaCl₂ = Molarity * Volume of solution (in liters).

However, without the volume of the solution, it's not possible to calculate the exact number of moles needed. The molarity only represents the concentration of the solution, not the actual amount of solute required.

To determine the moles of CaCl₂ needed, you would need to know the volume of the water or the desired final volume of the solution.