Question

Please please help!

Answer 1

 The mass  percent  of potassium chloride  is   1.386%

calculation

mass  percent = actual mass/ Theoretical mass x 100

Actual mass = 9.35 g

Theoretical mass  is  calculated as below

Step 1 : write the equation for reaction

KCl + H₂O  →   KOH + HCl

Step 2: find the moles of H₂O

moles = mass÷ molar mass

The molar mass of H₂O = (2 x1 ) +(16)  = 18 g/mol

moles is therefore = 162.98 g÷ 18 g/mol =9.054 moles

Step 3: use the mole ratio to determine the moles of KCl

KCl: H₂O  is 1:1 therefore the moles of KCl  is also = 9.054 moles

Step 4:  find the  theoretical mass of KCl

mass = moles x molar mass

from periodic table the  molar mass of KCl = 39 +35.5 =74.5 g/mol

mass = 9.054 moles x 74.5 g/mol =674.5 g

Theoretical mass is therefore = 9.35 g/ 674.5 g x 100 = 1.386%