1. If it takes 67 mL of 0.15 M NaOH to neutralize 134 mL of an HCl solution, what is the concentration of the HCl?

2. If it takes 27.4 mL of 0.050 M H2SO4 to neutralize 357 mL of KOH solution, what is the concentration of the KOH solution?

3. If it takes 55 mL of 0.5 M NaOH solution to completely neutralize 130 mL of sulfuric acid solution (H2SO4), what is the concentration of the H2SO4 solution?

The answer to your question is 1) 0.0075  2) 0.0077   3) 0.0105

Explanation:

1.-

Chemical reaction

               NaOH + HCl  ⇒    NaCl   +   H₂O

Calculate the moles of reactants

Molarity = moles / volume

moles = molarity x volume

moles = 0.15 x 0.067

          = 0.001005 moles of NaOH

               1 moles of NaOH 1 moles of HCl

               0.001005 moles    x

                x = (0.001005 x 1)/ 1 = 0.001005 moles of HCl

Concentration of HCl = 0.001005/0.134

                                   = 0.0075 M

2)

Chemical reaction

         H₂SO₄   +   2KOH  ⇒   K₂SO₄  +  2H₂O

Calculate the moles of H₂SO₄

moles = molarity x volume

moles = 0.05 x 0.0274

moles = 0.00137

        1 mol of H₂SO₄ 2 moles of KOH

        0.00137              x

         x = (0.00137 x 2) / 1

         x = 0.00274 moles

Calculate the molarity

Molarity = 0.00274/0.357

Molarity = 0.0077

3)

Chemical reaction

      2NaOH  +   H₂SO₄   ⇒    Na₂SO₄   +   2H₂O

Calculate the moles of NaOH

moles = molarity x volume

moles = 0.5 x 0.055

          = 0.0275

         2 moles of NaOH  1 mol of H₂SO₄

          0.0275 moles        x

           x = (0.0275 x 1)/2

           x = 0.01375 moles of H₂SO₄

Molarity = 0.01375/0.130

Molarity = 0.0105

"the periodic table is arranged in order of atomic number."

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"