calculate the theortetical percentage of water for the following hydrates.
Calcium nitrate tetrahydrate
Ca(No3)2 X 4H2O
100%
To calculate the theoretical percentage of water in a hydrate, you will need to determine the molecular weights of both the water and the anhydrous compound. Then, using the equation:
Percentage of water = (Molecular weight of water / Molecular weight of hydrate) x 100
Step 1: Determine the molecular weight of water (H2O)
The molecular weight of water (H2O) can be calculated by adding the atomic weights of hydrogen (H) and oxygen (O).
H = 1 gram/mole
O = 16 grams/mole
Molecular weight of water (H2O): 2(1) + 16 = 18 grams/mole
Step 2: Determine the molecular weight of the hydrate (Ca(NO3)2 · 4H2O)
The molecular weights of calcium (Ca), nitrogen (N), oxygen (O), and hydrogen (H) can be obtained from the periodic table.
Ca = 40 grams/mole
N = 14 grams/mole
O = 16 grams/mole
H = 1 gram/mole
Molecular weight of Ca(NO3)2: 40 + 2(14) + 6(16) = 164 grams/mole
To calculate the molecular weight of the hydrate:
Molecular weight of hydrate (Ca(NO3)2 · 4H2O) = Molecular weight of Ca(NO3)2 + 4(Molecular weight of water)
Step 3: Calculate the percentage of water
Using the equation mentioned earlier:
Percentage of water = (Molecular weight of water / Molecular weight of hydrate) x 100
Percentage of water = (18 / (164 + 4(18))) x 100
Simplifying the equation:
Percentage of water = (18 / (164 + 72)) x 100
Percentage of water = (18 / 236) x 100
Percentage of water = 7.63%
Therefore, the theoretical percentage of water in Calcium nitrate tetrahydrate (Ca(NO3)2 x 4H2O) is approximately 7.63%.