Edexcel IGCSE Chemistry 2.14 Greenhouse gases
Practise planning oxygen-in-air experiments using a metal or non-metal and interpreting volume changes when oxygen is removed.
- Syllabus
- First assessment 2019
- Course
- Chemistry 4CH1
2.14 Oxygen percentage practical question 1
When iron is left in damp air, rust forms on its surface.
Question (a)
(a)
A student uses this apparatus to find the approximate percentage by volume of oxygen in air.
This is the student's method.
- place a graduated glass tube in a beaker of water
- place some damp iron wool and a rubber bung in the top of the tube
- record the reading of the water level in the tube
- leave the apparatus for a few days
- record the reading of the water level again
The diagram shows the readings at the start and at the end of the experiment.
[ 3 ]
Question (i)
(i)
Use the readings to complete the table, giving all values to the nearest 0.5 cm3.
[ 2 ]
Question (ii)
(ii)
The student uses these results to calculate the percentage by volume of oxygen in air.
Suggest why her calculated value is lower than the expected value.
[ 1 ]
Question (b)
(b)
The student repeats the experiment using the same apparatus.
These are her results for the second experiment.
volume of air in tube at start = 80.0 cm3
reading at start = 20.0
reading at end = 35.5
Use the results to calculate the percentage by volume of oxygen in air.
percentage = ................................ %
[ 3 ]
All question bank results loaded