Question

In: Chemistry

A 0.3146-g sample of a mixture of NaCl(s) and KBr(s) was dissolved in water. The resulting...

A 0.3146-g sample of a mixture of NaCl(s) and KBr(s) was dissolved in water. The resulting solution required 36.00 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.

Solutions

Expert Solution

Let mass of NaCl be m gram
Then mass of KBr will be (0.3146-m) g

Molar mass of NaCl= 58.5 g/mol
number of moles of NaCl = mass / molar mass
                                                    = m/58.5

Molar mass of KBr= 199 g/mol
number of moles of NaCl = mass / molar mass
                                                    = (0.3146- m) /199
So, total number of moles of Cl- and Br - = m/58.5   + (0.3146- m) /199

Number of moles of AgNO3 required = M*V
                                                                             = 0.08765*0.036    (since volume is 36 mL= 0.036 L)
                                                                             =3.16*10^-3 mol

Number of moles of AgNo3 = number of moles of Cl- and Br
3.16*10^-3 = m/58.5   + (0.3146- m) /199
3.16*10^-3 = (199*m+ 58.5* (0.3146- m)) /(199*58.5)
3.16*10^-3 = (199*m+ 18.4 - 58.5*m) /(11641.5)
36.79 = 140.5 m + 18.4
m = 0.1309 g

mass % of NaCl = mass of NaCl * 100 / total mass
    = 0.1309 * 100 / 0.3146
    = 41.6 %
Answer: 41.6 %


Related Solutions

A 0.444 g sample contained only NaCl and KBr. It was dissolved in water and required...
A 0.444 g sample contained only NaCl and KBr. It was dissolved in water and required 81.13 mL of 0.05664 M AgNO3 for complete titration of both halides (giving AgCl (s) and AgBr (s)). Calculate the mass of KBr in the solid sample.
A 0.9140 g sample of a mixture of NaCl and KCl is dissolved in water, and...
A 0.9140 g sample of a mixture of NaCl and KCl is dissolved in water, and the solution is then treated with an excess of AgNO3 to yield 1.943 g of AgCl. Calculate the percent by mass of each compound in the mixture.
A 0.9000 g sample of a mixture of NaCl and KCl is dissolved in water, and...
A 0.9000 g sample of a mixture of NaCl and KCl is dissolved in water, and the solution is then treated with an excess of AgNO3 to yield 1.923 g of AgCl. Calculate the percent by mass of each compound in the mixture. ____% mass of NaCl ____% mass of KCl
A 0.2368 sample contained only NaCl and KBr. It was dissolved in water and required 44.80...
A 0.2368 sample contained only NaCl and KBr. It was dissolved in water and required 44.80 mL of 0.04873 M AgNO3 for complete titration of both halides. Calculate the weight percent of Br in the solid sample. (answer is 60.85 but please show work)
A mixture contains only and . A 4.51-g sample of the mixture is dissolved in water...
A mixture contains only and . A 4.51-g sample of the mixture is dissolved in water and an excess of is added, producing a precipitate of . The precipitate is filtered, dried, and weighed. The mass of the precipitate is 1.06 g. What is the mass percent of in the sample? %
If 17.5 g of NaCl is dissolved in 100. g of water, what is the mass...
If 17.5 g of NaCl is dissolved in 100. g of water, what is the mass % concentration of NaCl in this solution? Note: 1. Use 3 sig figs for your final answer. 2. Do not answer as fractions. For example, if you think 30% is the correct answer, either "30" or "30%" will be accepted, but "0.30" will not. "30%" will actually be converted to 30 automatically
A 19.04 g mixture of sugar (C12H22O11) and table salt (NaCl) is dissolved in 233 g...
A 19.04 g mixture of sugar (C12H22O11) and table salt (NaCl) is dissolved in 233 g of water. The freezing point of the solution was measured as -3.58 °C. Calculate the mass percent of sugar in the mixture. A list of Kf values can be found here.
A 15.86 g mixture of sugar (C12H22O11) and table salt (NaCl) is dissolved in 145 g...
A 15.86 g mixture of sugar (C12H22O11) and table salt (NaCl) is dissolved in 145 g of water. The freezing point of the solution was measured as -4.45 °C. Calculate the mass percent of sugar in the mixture.
A 13.13 g mixture of sugar (C12H22O11) and table salt (NaCl) is dissolved in 253 g...
A 13.13 g mixture of sugar (C12H22O11) and table salt (NaCl) is dissolved in 253 g of water. The freezing point of the solution was measured as -2.41 °C. Calculate the mass percent of sugar in the mixture. Solvent Formula Kf value* (°C/m) Normal freezing point (°C) Kb value (°C/m) Normal boiling point (°C) water H2O 1.86 0.00 0.512 100.00
A 19.57 g mixture of sugar (C12H22O11) and table salt (NaCl) is dissolved in 223 g...
A 19.57 g mixture of sugar (C12H22O11) and table salt (NaCl) is dissolved in 223 g of water. The freezing point of the solution was measured as -3.85 °C. Calculate the mass percent of sugar in the mixture. A list of Kf values can be found here.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT