This is acids, bases, buffers and salts lab... 1.Obtain three small beakers. Lab

Question

This is acids, bases, buffers and salts lab...

1.Obtain three small beakers. Label them 1, 2 and 3. Pour 50 mL of 0.10 M HCl in the first beaker.

2. Pour 5.0 mL of this solution into your clean, dry 100 mL graduate cylinder. Add distilled water until the 50.0 mL mark and pour the mixture into the second beaker and mix well.

3. Pour 5.0 mL of the solution in the second beaker into the graduate cylinder and dilute this to 50.0 mL. Pour this into the third beaker and mix well.

and also 0.10M NaOH

PH(HCl) : beaker #1: 4.7 #2: 4.3 #3: 2.3

PH(NaOH) : beaker #1 : 12.3 #2: 11.6 #3: 10.9

(1)Calculate the concentration of HCl or NaOH in each of the solutions you measured using the dilution equation: M1V1 = M2V2.

(2)By how many units did the pH of a solution of a strong base or acid change when it was diluted by a factor of ten?

Explanation / Answer

(1). In beaker 1 -

Concentration of HCl = 0.10 M

Concentration of NaOH = 0.10 M

In beaker 2 -

Moles of HCl poured = 5*0.10

= 0.5 milimoles

Amount of water added = 50 mL

Concentration of HCl = 0.5 / 50

= 0.01 M

Similarly, concentration of NaOH = 0.01 M

In beaker 3 -

Moles of HCl poured = 5*0.01

= 0.05 milimoles

Amount of water added = 50 mL

Concentration of HCl = 0.05 / 50

= 0.001 M

Similarly, Concentration of NaOH = 0.001 M

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