1. An 887.0 mg sample of a mixture containing only NaCl and KCl is dissolved in water, and excess AgNO3 is added to yield 1.913 g of AgCl. Compute the mass-% of each compound in the mixture.
hi! in order to solve this you will need to incorporate a bit of algebra. first off, you have to produce the equations for each reactions.
NaCl + AgNO3 ---> AgCl + NaNO3
KCl + AgNO3 ---> AgCl + NaNO3
and let NaCl = x ; KCl = y
since the sample is equal to 0.887, and your sample contains only NaCl and KCl, then we have our first equation as:
x + y = 0.887 ----- (1)
and our precipitate is equal to 1.913. In order to complete the equation for the precipitate, we will relate NaCl to AgCl and KCl to AgCl by:
AgCl from NaCl:
x milligrams NaCl * (Mol wt AgCl/Mol wt NaCl)
x mg NaCl * (143.32 mg AgCl/58.44 mg NaCl) = 2.45x
and AgCl from KCl:
y milligrams KCl * (Mol wt AgCl/Mol wt KCl)
y mg NaCl * (143.32 mg AgCl/74.55 mg KCl) = 1.92y
with this, our second equation for the precipitate will be:
2.45x + 1.92y = 1.913 ---- (2)
Now, with our first and second equation, with two equations and 2 unknowns, input in your calculator and you will get an answer equal to:
x (NaCl) = 0.3962 mg
y (KCl) = 0.4908 mg
Now we can get the percent NaCl and KCl:
%NaCl = (0.3962/0.887)*100
%NaCl = 44.67% (ANSWER)
%KCl = (0.4908/0.887)*100
%KCl = 55.33 (ANSWER)
Hope this helped!! :)
To compute the mass-% of each compound in the mixture, we need to first calculate the masses of NaCl and KCl present in the 1.913 g of AgCl formed.
1. Calculate the moles of AgCl formed:
- The molar mass of AgCl is 143.32 g/mol.
- Dividing the mass of AgCl formed by its molar mass gives us the moles of AgCl:
Moles of AgCl = 1.913 g / 143.32 g/mol = 0.0134 mol
2. Determine the moles of Cl in AgCl:
- Since AgCl contains one Cl atom per molecule, its amu value is equal to the amu value of Cl.
- The molar mass of Cl is 35.45 g/mol.
- Thus, the moles of Cl in AgCl is equal to 0.0134 mol.
3. Calculate the moles of NaCl:
- NaCl contains one Cl atom per molecule, so the moles of Cl in NaCl is equal to the moles of Cl in AgCl.
- Therefore, the moles of NaCl is also equal to 0.0134 mol.
4. Calculate the mass of NaCl and KCl:
- To find the mass of NaCl and KCl in the mixture, we need to multiply their respective moles by their respective molar masses.
Mass of NaCl = 0.0134 mol * (22.99 g/mol + 35.45 g/mol) = 0.768 g
Mass of KCl = 0.0134 mol * (39.10 g/mol + 35.45 g/mol) = 0.839 g
5. Calculate the mass-% of each compound:
- The mass-% of a compound is calculated by dividing the mass of the compound by the total mass of the mixture and multiplying by 100.
Mass-% of NaCl = (0.768 g / 1.913 g) * 100 = 40.18%
Mass-% of KCl = (0.839 g / 1.913 g) * 100 = 43.87%
Therefore, the mass-% of NaCl in the mixture is 40.18% and the mass-% of KCl is 43.87%.
To calculate the mass-% of each compound in the mixture, we need to determine the individual masses of NaCl and KCl present in the sample.
Let's start by converting the mass of AgCl formed to moles of AgCl. We'll use the molar mass of AgCl to do this calculation.
The molar mass of AgCl consists of the atomic masses of silver (Ag) and chlorine (Cl), which are approximately 107.87 g/mol and 35.45 g/mol, respectively:
Molar mass of AgCl = (1 * molar mass of Ag) + (1 * molar mass of Cl)
= (1 * 107.87 g/mol) + (1 * 35.45 g/mol)
= 143.32 g/mol
Now we can calculate the number of moles of AgCl formed in the reaction:
Number of moles of AgCl = mass of AgCl / molar mass of AgCl
= 1.913 g / 143.32 g/mol
= 0.01337 mol AgCl
Since AgCl is formed from the reaction between AgNO3 and the chloride ions from NaCl and KCl, the molar ratio is 1:1. This means that the number of moles of AgCl formed is equal to the total number of moles of chloride ions from NaCl and KCl.
Since the molar ratio is 1:1, the number of moles of NaCl + KCl is also 0.01337 mol.
To find the individual masses of NaCl and KCl, we need to convert the moles of each compound to grams using their respective molar masses.
The molar mass of NaCl is approximately 22.99 g/mol for sodium (Na) and 35.45 g/mol for chlorine (Cl). The molar mass of KCl is approximately 39.10 g/mol for potassium (K) and 35.45 g/mol for chlorine (Cl).
Mass of NaCl = moles of NaCl * molar mass of NaCl
= 0.01337 mol * (22.99 g/mol + 35.45 g/mol)
= 0.724 g
Mass of KCl = moles of KCl * molar mass of KCl
= 0.01337 mol * (39.10 g/mol + 35.45 g/mol)
= 1.207 g
Finally, we can calculate the mass-% of each compound in the mixture:
Mass-% of NaCl = (mass of NaCl / total mass of mixture) * 100
= (0.724 g / 0.887 g) * 100
= 81.70%
Mass-% of KCl = (mass of KCl / total mass of mixture) * 100
= (1.207 g / 0.887 g) * 100
= 136.18%
Please note that the mass-% of KCl seems to be higher than 100% because there might have been some experimental error in the calculations or measurements. In such cases, it is common to find a mass-% value exceeding 100%.
Set up two equation. They are
(1) g NaCl + g KCl = 0.8870g
(2) g AgCl from NaCl + g AgCl from KCl = 1.913g
If you let X = g NaCl
and let Y = g KCl, then equation 1 becomes X+Y = 0.8870 and equation 2 becomes
X(MMAgCl/MMNaCl) + Y(MMAgCl/MMKCl) = 1.913 where MM stands for molar mass.
Solve the two equation simultaneously for X and Y, then
%NaCl = (X/0.8870)*100 = ?
%KCl = (Y/0.8870)*100 = ?