A 0.3146-g sample of a mixture of NaCl(s) and KBr(s) was dissolved in water. The resulting solution required 47.40 mL of 0.08765 M AgNO3(aq) to precipitate the Cl–(aq) and Br–(aq) as AgCl(s) and AgBr(s). Calculate the mass percentage of NaCl(s) in the mixture

Two equations in two unknowns to be solved simultaneously.

Let x = mass NaCl
and y = mass KBr
-----------------
equation 1 is x + y = 0.3146

equation 2 is
(x/molar mass NaCl) + (y/molar mass KBr) = 0.04740*0.08765

Solve for x, then
%NaCl = (x/mass mixture)*100 = ?
Post your work if you get stuck.

Ah, chemistry! The subject that makes some people say, "I ion-ly understand a few things!" So, let's calculate the mass percentage of NaCl in the mixture, shall we?

First, let's find out the number of moles of AgNO3 used. We can do this using the formula:

moles = concentration × volume

So, moles of AgNO3 = 0.08765 mol/L × 0.04740 L = 0.00414966 mol

Now, since we have a mixture of NaCl and KBr, we can use stoichiometry to find the moles of Cl- in the mixture. Since 1 mole of AgNO3 reacts with 1 mole of Cl-, the moles of Cl- present in the mixture is also 0.00414966 mol.

Since NaCl is the only source of Cl- in this case, the moles of NaCl is also equal to 0.00414966 mol. We can calculate the mass of NaCl now, using its molar mass of 58.44 g/mol.

mass of NaCl = moles of NaCl × molar mass of NaCl = 0.00414966 mol × 58.44 g/mol = 0.2420 g

Finally, to calculate the mass percentage of NaCl in the mixture, we divide the mass of NaCl by the total mass of the mixture and multiply by 100:

mass percentage of NaCl = (0.2420 g / 0.3146 g) × 100 = 77.04%

So, the mass percentage of NaCl in the mixture is approximately 77.04%.

To calculate the mass percentage of NaCl in the mixture, we need to determine the amount of NaCl and KBr in the sample.

1. Calculate the moles of AgNO3 used:
Moles of AgNO3 = (volume of AgNO3 solution (L)) x (molarity of AgNO3 (mol/L))
Moles of AgNO3 = 0.04740 L x 0.08765 mol/L

2. Calculate the moles of Cl- and Br- ions in the sample:
Moles of Cl- and Br- = Moles of AgNO3 (since AgNO3 reacts with Cl- and Br- ions in a 1:1 ratio)

3. Calculate the moles of NaCl and KBr in the sample:
Moles of NaCl/KBr = Moles of Cl- and Br- / 2 (since NaCl and KBr both provide one Cl- or Br- ion per formula unit)

4. Calculate the mass of NaCl and KBr in the sample:
Mass of NaCl/KBr = Moles of NaCl/KBr (mol) x Molar mass of NaCl/KBr (g/mol)

5. Calculate the mass percentage of NaCl in the mixture:
Mass percentage of NaCl = (Mass of NaCl / Mass of mixture) x 100%

Note: To find the molar mass of NaCl, KBr, and AgNO3, you can refer to the periodic table.

Now, let's go ahead and perform the calculations.

The molar mass of NaCl is 58.44 g/mol, and the molar mass of KBr is 119.0 g/mol.

81.4%