Mr Cole Chemistry

Uses of Group 2 Elements Questions

Uses of Group 2

Group 2 and Group 7 Worksheet

1. Complete the table below with the major uses for the elements and compounds.

The questions below give away the answers to the table. Please try to complete the table before reading them.

Element / Compound Major Use
Magnesium (Mg)
Magnesium Hydroxide (Mg(OH)2)
Calcium Oxide (CaO) / Calcium Carbonate (CaCO3)
Barium Chloride (BaCl2)
Barium Sulfate (BaSO4)
Reveal Completed Table
Element / Compound Major Use
Magnesium (Mg) Extraction of Titanium
Magnesium Hydroxide (Mg(OH)2) Antacid (Neutralising excess stomach acid)
Calcium Oxide (CaO) / Calcium Carbonate (CaCO3) Flue Gas Desulfurisation (Removing acidic gases)
Barium Chloride (BaCl2) Testing for Sulfate ions
Barium Sulfate (BaSO4) Medical X-Rays (Barium Meal)
2. Magnesium’s ability to extract other metals relates to its position on the reactivity series.
a) Write an equation for the reaction between magnesium and the titanium ore.
TiCl4 + 2Mg
→
Ti + 2MgCl2

Note: The titanium ore (Rutile, TiO2) is first converted to Titanium(IV) Chloride (TiCl4) before it is reduced by Magnesium in the Kroll Process.

b) State what type of reactant magnesium is behaving as in this reaction.

Reducing agent (It donates electrons to the Titanium ions).

3. Write an equation for the action of magnesium hydroxide as an antacid.
Mg(OH)2(s) + 2HCl(aq)
→
MgCl2(aq) + 2H2O(l)
4. The use of calcium oxide and calcium carbonate as flue gas scrubbers can be represented in several ways.
a) Write an equation for the reaction between calcium oxide and sulfur dioxide.
CaO(s) + SO2(g)
→
CaSO3(s)
b) Sulfur dioxide dissolves in water to form an acid. Write an equation for this reaction.
SO2(g) + H2O(l)
→
H2SO3(aq)
c) Write an equation for the reaction between calcium oxide and the acid formed in the previous question.
CaO(s) + H2SO3(aq)
→
CaSO3(s) + H2O(l)
d) Write an equation for the reaction between calcium carbonate and sulfur dioxide.
CaCO3(s) + SO2(g)
→
CaSO3(s) + CO2(g)
5. Barium chloride is used as a chemical test.
a) Write an equation for the reaction between barium chloride and iron (II) sulfate.
BaCl2(aq) + FeSO4(aq)
→
BaSO4(s) + FeCl2(aq)
b) State the step prior to the reaction above and explain why it is necessary.

Acidify the solution using dilute hydrochloric acid or nitric acid. This removes any carbonate ions (CO32-) present in the solution, which would otherwise react with barium to form a white precipitate of Barium Carbonate, giving a false positive.

6. Barium sulfate is used in medicine.
a) Describe the use of barium sulfate by doctors.

It is used as a Barium Meal. It is given to patients to swallow. Barium sulfate is opaque to X-rays (it absorbs them), unlike the soft tissue of the gut. This allows the structure of the digestive system to appear clearly on an X-ray image for diagnosis.

b) Explain why barium sulfate can be used in this way but barium nitrate cannot.

Barium sulfate is insoluble, so it is not absorbed into the bloodstream. Barium nitrate is soluble, so it would dissolve and be absorbed. Since free Barium ions (Ba2+) are toxic, using barium nitrate would poison the patient.

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