Formula for Weight
Home page
Formula for Resultant Force
Formulas for Kinematics
Describe the trend in reactivity and melting and boiling point going down Group VII.
Going down Group VII, reactivity decreases while melting and boiling point increases.
Describe the trend in reactivity and melting point going down Group I.
Going down Group I, reactivity increases, while melting point decreases.
Describe, with the help of chemical equations, the reactions in the blast furnace which help to purify molten iron.
Limestone is decomposed by heat to form calcium oxide and carbon dioxide.
CaCO3 (s) –> CaO (s) + CO2 (g)
Calcium oxide reacts with the main acidic impurity, silicon dioxide to form molten slag.
CaO (s) + SiO2 (s) –> CaSiO3 (l)
Describe, with the help of chemical equations, the reactions in the blast furnace which lead to the production of molten iron.
Coke reacts with oxygen in the air to form carbon dioxide.
C (s) + O2 (g) –> CO2 (g)
Coke then reacts with carbon dioxide to form carbon monoxide.
C (s) + CO2 (g) –> 2CO (g)
Carbon monoxide reduces haematite to form molten iron and carbon dioxide.
Fe2O3 (s) + 3CO (g) –> 2Fe (l) + 3CO2 (g)
Describe the test for iodide ions.
Add dilute nitric acid, followed by silver nitrate solution. If a yellow precipitate forms, it shows the presence of iodide ions.
List down the two base chemical properties.
- Bases react with acids to form a salt and water only (neutralization).
- Bases react with ammonium salts to produce ammonia gas, water and salt.
List down the three acidic chemical properties.
- Acids react with reactive metals to form hydrogen and salt.
- Acids react with carbonates to form a salt, carbon dioxide and water.
- Acids react with bases to form a salt and water only (neutralization).