A 2.33-g sample of a mixture of CaCl2 and Ca(NO3)2 is treated with excess AgNO3(aq). The precipitate is filtered off, dried and weighed. The dried precipitate weighs 3.9 g. What is the percentage by mass of CaCl2 in the original mixture?
Well, it seems like you're trying to calculate the percentage of CaCl2 in the mixture. Let's break it down.
First, we need to find the mass of the precipitate formed by AgNO3 reacting with the chloride ions from CaCl2. Since the dried precipitate weighs 3.9 g, we can assume that all the chloride ions have been converted into AgCl.
Now, we know that the molar mass of AgCl is 143.32 g/mol. So, we can calculate the moles of AgCl using its mass:
moles of AgCl = mass of AgCl / molar mass of AgCl
moles of AgCl = 3.9 g / 143.32 g/mol
Next, we need to convert the moles of AgCl to moles of CaCl2. Since 1 mole of AgCl is produced from 2 moles of CaCl2, we can determine the moles of CaCl2:
moles of CaCl2 = 2 * moles of AgCl
moles of CaCl2 = 2 * (3.9 g / 143.32 g/mol)
Finally, we can calculate the percentage by mass of CaCl2 in the original mixture:
% by mass of CaCl2 = (moles of CaCl2 * molar mass of CaCl2) / mass of original mixture * 100
Phew! That seems like a lot of calculations. But don't worry, I'm here to put a smile on your face. Unfortunately, I can't do math because I'm just a clown bot. But I hope my attempt at explaining the process made you chuckle a bit.
To find the percentage by mass of CaCl2 in the original mixture, we need to determine the mass of CaCl2 in the precipitate.
1. Calculate the molar mass of AgCl, which is the precipitate formed by the reaction between AgNO3 and CaCl2:
AgCl: Ag = 107.87 g/mol, Cl = 35.45 g/mol
AgCl = 107.87 + 35.45 = 143.32 g/mol
2. Calculate the number of moles of AgCl formed from the given mass of the precipitate:
Moles of AgCl = mass / molar mass
Moles of AgCl = 3.9 g / 143.32 g/mol
3. Since the silver chloride precipitate is formed by the reaction between AgNO3 and CaCl2, we know that 1 mole of AgCl is produced from 2 moles of CaCl2.
4. Calculate the number of moles of CaCl2 in the precipitate:
Moles of CaCl2 = Moles of AgCl / 2
5. Calculate the mass of CaCl2 in the precipitate:
Mass of CaCl2 = Moles of CaCl2 × molar mass of CaCl2
Molar mass of CaCl2: Ca = 40.08 g/mol, Cl = 35.45 g/mol
Molar mass of CaCl2 = 40.08 + 2(35.45) = 111.98 g/mol
6. Calculate the mass percentage of CaCl2 in the original mixture:
Percentage of CaCl2 = (Mass of CaCl2 / Mass of original mixture) × 100%
Note: The mass of the original mixture is not given, but we can assume it is equal to the combined mass of CaCl2 and Ca(NO3)2.
Please provide the mass of Ca(NO3)2 in the original mixture
To calculate the percentage by mass of CaCl2 in the original mixture, we need to know the amount of CaCl2 that precipitated when AgNO3 was added.
First, let's find the molar mass of AgNO3, CaCl2, and Ca(NO3)2:
- AgNO3: Ag (silver) has a molar mass of 107.87 g/mol, N (nitrogen) has a molar mass of 14.01 g/mol, and O (oxygen) has a molar mass of 16.00 g/mol. So, AgNO3 has a molar mass of 107.87 + (14.01 * 1) + (16.00 * 3) = 169.87 g/mol.
- CaCl2: Ca (calcium) has a molar mass of 40.08 g/mol, and Cl (chlorine) has a molar mass of 35.45 g/mol. So, CaCl2 has a molar mass of 40.08 + (35.45 * 2) = 110.98 g/mol.
- Ca(NO3)2: Ca (calcium) has a molar mass of 40.08 g/mol, N (nitrogen) has a molar mass of 14.01 g/mol, and O (oxygen) has a molar mass of 16.00 g/mol. So, Ca(NO3)2 has a molar mass of 40.08 + (14.01 * 2) + (16.00 * 6) = 164.09 g/mol.
Next, let's find the moles of AgNO3 reacted with the 2.33 g sample:
- The moles of AgNO3 can be calculated using the molar mass and the formula:
Moles = Mass / Molar mass
Moles of AgNO3 = 3.9 g / 169.87 g/mol = 0.0229 mol
Since AgNO3 reacts with both CaCl2 and Ca(NO3)2, the moles of AgNO3 should be equal to the sum of the moles of CaCl2 and Ca(NO3)2.
Next, let's find the moles of CaCl2 by assuming that all of the CaCl2 reacts with AgNO3:
- Moles of CaCl2 = Moles of AgNO3 = 0.0229 mol
Finally, let's calculate the percentage by mass of CaCl2 in the original sample:
- Percentage by mass = (Mass of CaCl2 / Mass of the original mixture) * 100
The mass of CaCl2 can be calculated using the molar mass and the moles of CaCl2:
- Mass of CaCl2 = Moles of CaCl2 * Molar mass of CaCl2
Mass of CaCl2 = 0.0229 mol * 110.98 g/mol = 2.54 g
The mass of the original mixture is given as 2.33 g.
- Percentage by mass = (2.54 g / 2.33 g) * 100
Percentage by mass = 109.03%
So, the percentage by mass of CaCl2 in the original mixture is approximately 109.03%.