To determine the formula of hydrated copper sulfate, we need to find the number of moles of each component (copper sulfate and water) in the given weights and calculate the ratio between them.
Let's start by finding the number of moles of anhydrous copper sulfate (CuSO4). We can use the formula:
moles = mass / molar mass
The molar mass of CuSO4 is calculated by adding up the atomic masses of copper (Cu), sulfur (S), and four oxygen (O) atoms:
Cu: atomic mass = 63.55 g/mol
S: atomic mass = 32.07 g/mol
O: atomic mass = 16.00 g/mol
Molar mass of CuSO4 = (1 * 63.55) + (1 * 32.07) + (4 * 16.00) = 159.61 g/mol
Now, let's calculate the number of moles of anhydrous copper sulfate:
moles of CuSO4 = 1.94 g / 159.61 g/mol = 0.01214 mol
Next, we'll find the number of moles of water in the hydrated copper sulfate. To do this, we subtract the mass of anhydrous copper sulfate from the total mass of the compound:
moles of water = (3.05 g - 1.94 g) / 18.02 g/mol = 0.06104 mol
Now that we have the moles of copper sulfate and water, we need to determine their mole ratio. We divide the moles of water by the moles of copper sulfate to get the simplest whole number ratio:
0.06104 mol / 0.01214 mol โ 5
This tells us that for every 1 mole of anhydrous copper sulfate, there are approximately 5 moles of water.
Finally, we can write the formula of the hydrated copper sulfate:
CuSO4 ยท 5H2O
This means that each formula unit of hydrated copper sulfate contains one copper sulfate ion (CuSO4) and five water molecules (H2O).