What is the percent weight composition of water in plaster of paris?

Explanation

To find the percent weight composition of water in Plaster of Paris (Calcium Sulfate Hemihydrate), we can follow these steps:

### Step 1: Determine the molecular formula of Plaster of Paris
Plaster of Paris is known as Calcium Sulfate Hemihydrate, which can be represented as \( \text{CaSO}_4 \cdot \frac{1}{2} \text{H}_2\text{O} \).

### Step 2: Calculate the molar mass of Plaster of Paris
To calculate the molar mass, we need to sum the atomic weights of all the atoms in the formula:

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