problem 2.
a sample of calcium chloride weighs 1.64g. it is dissolved in water and silver nitrate solution added.a precipitate of silver chloride weighing 4.24g was formed.determine
the percentage composition of each element.
the simple formular of calcium chloride.
show the full working, I don't understand
4.24 g AgCl x (1 mol AgCl/143.32 g AgCl) = ?? moles AgCl.
??moles AgCl x (35.453 g AgCl/mole AgCl) = xx grams Cl.
%Cl in the sample = (xx g Cl/1.64)*100 =
I get something like 63% but you need to do it more exacting. Subtract from 100 to get percent Ca.
Then take a 100 g sample and determine the formula. Post your work if you get stuck.
To determine the percentage composition of each element in calcium chloride, we need to find the molar masses of calcium chloride and silver chloride.
1. Calculate the number of moles of silver chloride precipitate:
- Given that the weight of the precipitate is 4.24g
- The molar mass of silver chloride (AgCl) is the sum of the atomic masses of silver (Ag) and chlorine (Cl), which are 107.87 g/mol and 35.45 g/mol, respectively.
- The molar mass of AgCl = 107.87 g/mol + 35.45 g/mol = 143.32 g/mol
- Number of moles of AgCl = mass of AgCl / molar mass of AgCl
= 4.24 g / 143.32 g/mol
2. Calculate the number of moles of calcium chloride:
- Given that the weight of calcium chloride is 1.64g
- The molar mass of calcium chloride (CaCl2) is the sum of the atomic mass of calcium (Ca) and twice the atomic mass of chlorine (Cl), which are 40.08 g/mol and 35.45 g/mol, respectively.
- The molar mass of CaCl2 = 40.08 g/mol + (2 * 35.45 g/mol) = 110.98 g/mol
- Number of moles of CaCl2 = mass of CaCl2 / molar mass of CaCl2
= 1.64 g / 110.98 g/mol
3. Calculate the percentage composition of calcium (Ca) in calcium chloride:
- The percentage composition of Ca = (moles of Ca / total moles) * 100
= (moles of CaCl2 / total moles) * 100
4. Calculate the percentage composition of chlorine (Cl) in calcium chloride:
- The percentage composition of Cl = (moles of Cl / total moles) * 100
= (2 * moles of CaCl2 / total moles) * 100
Note: In this case, the total moles are the moles of CaCl2 since it completely dissociates into 1 mole of calcium and 2 moles of chlorine.
5. Plug in the values to calculate the percentages.
The simple formula for calcium chloride is CaCl2.
By following these steps, you can determine the percentage composition of each element in calcium chloride.