Page 142 - Chemistry_Form_2

Chemistry
for Secondary Schools

Activity 5.13

Aim: To investigate the effect of heat on ammonium carbonate

Requirements: Spatula, 2 test tubes, test tube holder, heat source, cobalt(II)
FOR ONLINE READING ONLY
chloride paper, red litmus paper, ammonium carbonate, and
limewater
Procedure
1. Put a spatulaful of ammonium carbonate salt into a dry test tube.

2. Hold the test tube with a test tube holder and heat the salt over a non-
luminous flame.

3. Pass the gas evolved into a test tube containing limewater. Record the
observations.

4. Put a moist red litmus paper and cobalt(II) chloride paper at the mouth of
the test tube, and record the observations.

Questions

1. What differences did you observe between this activity and Activity 5.12?
2. What is the balanced chemical equation for the reaction in Step 3?

Action of heat on nitrates
Most nitrates decompose on heating to give the metal oxide, brown fumes of
nitrogen dioxide, and oxygen gas. Nitrates of alkali metals such as sodium and
potassium decompose slowly on heating to give oxygen and metal nitrite.

Nitrates of calcium and copper decompose into their respective oxides, nitrogen
dioxide gas, and oxygen gas.

Exceptional behaviours are shown by ammonium nitrate and silver nitrate.
Ammonium nitrate decomposes to give dinitrogen oxide gas and water, whereas
silver nitrate decomposes to give silver metal, nitrogen dioxide, and oxygen gas.

Student’s Book Form Two 135

01/08/2025 11:21:10
CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 135 01/08/2025 11:21:10
CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 135