S.5 Chemistry Test

End of Term 2 Chemistry Test based on the newly adapted A Level Curriculum

In this test, you will find three (3) questions for the end of term 2. Question one (1) is organic chemistry, two (2) is Inorganic chemistry and question three (3) is Physical chemistry.

If you would like to down the paper, click on the download button below to access the file. These will come periodically to assist learners in their chemistry education.

ITEM 1.

A group of forensic scientists are investigating organic substances they found at certain suspected illegal chemical dump. Analysis gave them the molecular formulae of the two compounds as M and N. To gather more information about the compounds, they also need to know the nature of the two compounds and their chemical reactions. They are very aware that you are studying chemistry in Arua Secondary and therefore you must be having a knowledge in organic chemistry. They have come to you for advice. 

Task:

As a chemistry student, help them to;

1. Name the compounds M and N, and state the functional groups in the compounds.
2. Predict the reaction and write the mechanism for the reaction of;

• M with dry hydrogen bromide
• N with chlorine in presence of UV Light
• M with conc sulphuric acid and the mixture warmed with water.
• N with concentrated nitric acid at 150-400 temperature in degree centigrade

1. Show how M can be obtained from Calcium carbonate.

ITEM 2

A team of scientists from S.5 Class went to Uganda Research Institute and were asked asked to design new heat-resistant electrical wires and lightweight non-metallic containers. They need to choose elements from period 3 of the periodic table. The scientists are puzzled. Some elements in the same row conduct electricity well, others do not. Some melt at very high temperatures, while others melt easily. They have asked you the S.5 science periodic detectives to analyze the data.

TASK:

Based on your analysis;

1. Compare the change in atomic radius down Group 1 with that across period 3, explaining the reasons for the differences.
2. Justify why the first ionization energy decreases from phosphorus to Sulphur, even if the nuclear charge increases?
3. Explain which period 3 element would you recommend for heat resistant electrical wires.
4. Explain which element you recommend for a lightweight, non-metallic containers.

ITEM 3.

Water treatment plant used chlorine to disinfect drinking water. The plant wanted to ensure that the chlorine levels are within safe limits. A mass spectrometer was used to analyze the chlorine before being used in the water treatment resulting in a mass spectrum with peaks at m/z 35 and 37. The abundance of the peaks at  m/z 35 was 75%, and the abundance of the peak at m/z 37 was 25%.

TASK

1. Calculate the average atomic mass of chlorine.
2. Describe the other applications of mass spectrometer or spectrometry.
3. Describe the limitations of mass spectrometry as an analytical technique.