Paper 1: pH Practical

Question 1

If you wanted a fixed volume of HCL for an experiment, what is the best piece of apparatus to use?

Answer 1

Volumetric pipette

Greater accuracy than a measuring cylinder

Question 2

How can you measure the pH of a solution?

Answer 2

Use a ph probe or add universal indicator and compare to a colour chart

Question 3

What is a neutralisation reaction?

Answer 3

Hydrogen ions reacting with hydroxide ions to form water

Question 4

When measuring the pH change of the combination of two reactants why is it important to stir the mixture after the reactants are combined?

Answer 4

To ensure a complete reaction and that the pH is consistent throughout the mixture

Question 5

How could an experiment measuring the pH using universal indicator paper be improved?

Answer 5

Use a pH probe to get an accurate reading

Question 6

Ca(OH)2 can be added to HCL for neutralisation. How do you know that the HCL has been fully neutralised?

Answer 6

The pH should be pH7 - neutral

Question 7

Ammonia solution is an alkali. What could be used to show it is alkaline?

Answer 7

Universal indicator turns blue

High ph probe value around 11

Question 8

Method of practical

Answer 8

Using the measuring cylinder or volumetric pipette, add 25cm2 of dilute HCL to a beaker

Add a few drops of universal indicator. Compare the intuyas colour of the solution to a pH colour chart and record the pH. Alternatively, a pH probe can be used

Add calcium hydroxide or calcium oxide (one level spatula at a time) to the beaker, stirring and recording the pH between additions

Stop adding calcium hydroxide/calcium oxide when the pH remains constant

Question 9

Equation for neutralisation with calcium oxide:

Answer 9

Question 10

Reaction using calcium hydroxide

Answer 10