Find the amount of substance and the number of molecules 180 g of malachite.

Decision:
First, let’s write down the chemical formula of malachite – CuSO4 * 5H2O.
In order to find the amount of a substance (number of moles), you must use the formula:
n (CuSO4 * 5H2O) = m (CuSO4 * 5H2O) / Mr (CuSO4 * 5H2O).
From this formula it follows that we need to calculate the molar mass of malachite.
The molar mass of malachite is:
Mr (CuSO4 * 5H2O) = Mr (Cu) + Mr (S) + 9 * Mr (O) + 10 * Mr (H) = 64 + 32 + 16 * 9 + 10 * 1 = 250 g / mol.
Next, we substitute in the formula:
n (CuSO4 * 5H2O) = 180/250 = 0.72 mol.
The number of molecules is calculated by the formula:
N = Na * n (CuSO4 * 5H2O) = 0.72 × 6.02 * 10 ^ 23 = 4.33 * 10 ^ 23.