1. The document provides a topical test with 6 questions about chemical equations and calculations. It asks the student to write chemical equations for reactions involving sodium, magnesium carbonate, aluminum, copper nitrate, and iron. It also asks the student to calculate relative molecular mass, mass of atoms, relative molecular mass of a gas, a combustion reaction of magnesium, and the volume and number of oxygen molecules from the decomposition of hydrogen peroxide.

1. Name :_______________________________________________________________________
Class : _______________________________
TOPICAL TEST CHAPTER 3
1. Write down the chemical equation of the following reactions
a. Sodium reacts with oxygen to produce a white metallic oxide.
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b. Chemical reaction between magnesium carbonate, MgCO3, and dilute hydrochloric acid,
HCl. Magnesium Chloride, MgCl2, water and carbon dioxide are formed.
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c. Aluminum reacts with copper (II) oxide to produce copper and aluminium oxide.
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d. When copper (II) nitrate is heated, it decomposes to produce copper (II) oxide, nitrogen
dioxide and oxygen.
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e. Iron reacts with chlorine, a brown iron (III) chloride is formed.
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2. Aspartame is an artificial sweetener that has no calorie. Its molecular formula is
C14H18N2O5. Calculate its relative molecular mass. [Ar: H=1; C=12; N=14; O=16]
3. Find the mass of the following:
a. 4.5 x 1022 chromium atom
b. 3 x 1024 helium atom
[Ar: Cr= 52; He= 4. NA= 6 x 1023 mol-1]

2. Name :_______________________________________________________________________
Class : _______________________________
4. 5.5 g of gas Y occupies a volume 3 dm3 at room temperature. Find the relative molecular
mass of gas Y. [Ar: C= 12; H= 1; O= 16; N= 14. 1 mole of gas occupies a volume 24 dm3 at
room temperature]
5. Magnesium can burn in oxygen to produce magnesium oxide.
a. Write the chemical equation showing the reaction.
b. Calculate the mass of magnesium oxide that formed if 4.8g of magnesium is burnt.
c. Calculate the volume of oxygen needed for this combustion 3g of magnesium at
room temperature.
[Ar: O= 16; Mg= 24. 1 mole of gas occupies a volume 24 dm3 at room temperature]

3. Name :_______________________________________________________________________
Class : _______________________________
6. Hydrogen peroxide, H2O2, decomposes to give water and oxygen. Write the chemical
equation showing the reaction. If 1.7g of Hydrogen peroxide decomposes, calculate
a. the volume of oxygen produced at room conditions.
b. the number of molecules of oxygen produced in the reaction.
[NA=6x1023 mol-1]