Calcium nitrate forms two different hydrated salts. One contains 24.7 % water and the other 30.4 % water. What are the formulas for these two hydrated salts?
formula for hydrated salt..
Ca(NO3)2xNH2O
so what is N?
percent water= N*molemassH20/(molmassCa(NO3)2 + molemassH2)
solve for N in each case.
To determine the formulas for the two hydrated salts of calcium nitrate, we need to analyze the percentage of water in each compound.
Let's start by calculating the percentage of anhydrous (water-free) calcium nitrate in each hydrated salt.
For the first hydrated salt, which contains 24.7% water:
1. Assume the total mass of the compound is 100 grams (since percentages are given).
2. The mass of the anhydrous salt is 100 - 24.7 = 75.3 grams.
3. Calcium nitrate has the chemical formula Ca(NO3)2, so its molar mass is calculated as:
Ca: 1 atom x 40.08 g/mol = 40.08 g/mol
N: 2 atoms x 14.01 g/mol = 28.02 g/mol
O: 6 atoms x 16.00 g/mol = 96.00 g/mol
Total molar mass of Ca(NO3)2 = 164.10 g/mol
4. Now, we can determine the number of moles of anhydrous calcium nitrate:
Moles = Mass / Molar mass = 75.3 g / 164.10 g/mol ≈ 0.459 mol
Based on the ratios in the chemical formula of calcium nitrate, we know that for every 1 mole of calcium nitrate, there are 2 moles of nitrate ions (NO3-) and 1 mole of calcium ions (Ca2+). Therefore, in 0.459 moles of calcium nitrate, there are 0.918 moles of nitrate ions and 0.459 moles of calcium ions.
Now let's consider the second hydrated salt, which contains 30.4% water:
1. Assuming the total mass of the compound is 100 grams.
2. The mass of the anhydrous salt is 100 - 30.4 = 69.6 grams.
3. Calculate the number of moles of anhydrous calcium nitrate:
Moles = Mass / Molar mass = 69.6 g / 164.10 g/mol ≈ 0.424 mol
4. Using the ratios, we find that in 0.424 moles of calcium nitrate, there are 0.848 moles of nitrate ions and 0.424 moles of calcium ions.
Now that we have the number of moles of calcium ions and nitrate ions for both hydrated salts, we can write the formulas.
Based on the mole ratios, the formulas for the two hydrated salts are as follows:
1. Hydrated salt with 24.7% water:
Ca(NO3)2 · 0.459H2O
2. Hydrated salt with 30.4% water:
Ca(NO3)2 · 0.424H2O