Question #24b1e

1 Answer
Apr 7, 2017

Answer:

The vinegar is 4.36 % acetic acid by mass.

Explanation:

Step 1. Write the balanced equation

#"CH"_3"COOH" + "NaOH" → "CH"_3"COONa" + "H"_2"O"#

Step 2. Calculate the moles of NaOH

#"Moles of NaOH" = "0.030 84" color(red)(cancel(color(black)("dm"^3color(white)(l) "NaOH"))) × "0.128 mol NaOH"/(1 color(red)(cancel(color(black)("dm"^3 color(white)(l)"NaOH")))) = "0.003 948 mol NaOH"#

Step 3. Calculate the moles of #"CH"_3"COOH"#

#"Moles of CH"_3"COOH" = "0.003 948" color(red)(cancel(color(black)("mol NaOH"))) × ("1 mol CH"_3"COOH")/(1 color(red)(cancel(color(black)("mol NaOH")))) = "0.003 948 mol CH"_3"COOH"#

Step 4. Calculate the mass of the #"CH"_3"COOH"#

#"Mass of CH"_3"COOH" = "0.003 948" color(red)(cancel(color(black)("mol CH"_3"COOH"))) × ("60.05 g CH"_3"COOH")/(1 color(red)(cancel(color(black)("mol CH"_3"COOH")))) = "0.2370 g CH"_3"COOH"#

Step 5. Calculate the mass percent of acetic acid.

#"Mass percent" = "mass of acetic acid"/"mass of vinegar" × 100 % = (0.2370 color(red)(cancel(color(black)("g"))))/(5.441 color(red)(cancel(color(black)("g")))) × 100 %#

#= 4.36 %#