1.1. Separate: Chemistry Only 

A student does a titration using dilute sulfuric acid to find the concentration of a solution of potassium hydroxide. The student adds 25.0 cm³ of the potassium hydroxide solution to a conical flask. He then adds a few drops of methyl orange indicator. The student does the titration four times.

i) Name the piece of apparatus the student should use to add the potassium hydroxide solution.

(1)

ii) What is the colour of methyl orange in an alkaline solution?

(1)

1.2. Separate: Chemistry Only 

The table shows the student’s results.

Concordant results are those within 0.20 cm³ of each other.

i) Place ticks (✔) in the table to show which results are concordant.

(1)

ii) Use the concordant results to calculate the mean (average) volume of acid added.

(2)

mean volume = .............................................................. cm³

1.3. Separate: Chemistry Only 

This table shows the student’s results for another titration.

The equation for the reaction is

2KOH + H₂SO₄ → K₂SO₄ + 2H₂O

i) Calculate the amount, in moles, of KOH in 25.0 cm³ of the potassium hydroxide solution.

(2)

amount of KOH = .............................................................. mol

ii) Calculate the amount, in moles, of H₂SO₄ in 21.20 cm³ of sulfuric acid.

(1)

amount of H₂SO₄ = .............................................................. mol

iii) Calculate the concentration, in mol/dm³, of the sulfuric acid.

(2)

concentration of sulfuric acid = .............................................................. mol/dm³