6 Chemical reactions

Practice questions on Chemical reactions

• Explain the difference between a physical change and a chemical change. Include one exampl… (4 marks, Explain)
• A student heats a piece of magnesium ribbon in air. The magnesium glows brightly and a whi… (4 marks, Describe)
• Iron rusts when it is exposed to both oxygen and water. Describe what happens to the iron … (4 marks, Describe)
• A student leaves an iron nail outside in the rain for several weeks. The nail becomes cove… (4 marks, Describe)
• Explain why increasing the temperature of a reaction mixture increases the rate of a chemi… (4 marks, Explain)
• Explain why breaking a large lump of a solid reactant into smaller pieces increases the ra… (4 marks, Explain)
• The industrial manufacture of ammonia uses the reversible reaction shown. N₂(g) + 3H₂(g) ⇌… (4 marks, Explain)
• Zinc powder is added to copper(II) sulfate solution. The blue colour of the solution fades… (4 marks, Explain)
• Magnesium ribbon is placed into dilute hydrochloric acid. Bubbles of gas are produced and … (4 marks, Explain)
• Chlorine gas is bubbled into potassium bromide solution. The colourless solution turns ora… (4 marks, Explain)
• Copper wire is placed into a solution of silver nitrate. Over time, the copper wire become… (4 marks, Explain)
• A student dissolves a dark brown solid, dinitrogen tetroxide (N₂O₄), in a sealed flask. Th… (4 marks, Explain)
• Explain why, in a closed system, a reversible reaction eventually reaches a state where th… (4 marks, Explain)
• Describe the effect on the equilibrium position of increasing the temperature of a reversi… (4 marks, Describe)
• Explain what is meant by a reversible reaction reaching a state of dynamic equilibrium in … (4 marks, Explain)
• A student adds a small piece of manganese(IV) oxide to a solution of hydrogen peroxide. Bu… (4 marks, Explain)
• A student investigates the reaction between marble chips (calcium carbonate) and dilute hy… (4 marks, Describe and explain)
• Explain why increasing the concentration of a dissolved reactant increases the rate of a c… (4 marks, Explain)
• A candle is made of wax. When a candle burns, liquid wax forms near the flame and a new wh… (4 marks, Justify)
• A chef dissolves sugar in hot water to make a syrup. Later, the chef accidentally burns so… (4 marks, Justify)