Reactions of acids and saltsIB MYP Sciences: Flashcards

Exam questions on Reactions of acids and salts

1. A student in Cairo adds a piece of magnesium ribbon to dilute sulfuric acid in a test tube. The mixture fizzes and the test tube becomes warm. When the student holds a lit splint at the mouth of the tube, it goes out with a squeaky pop.
   Write a word equation for the reaction between magnesium and dilute sulfuric acid.2 marks
2. A student in Seoul adds small chips of marble (calcium carbonate) to dilute hydrochloric acid in a conical flask on a balance. The mixture fizzes and the reading on the balance slowly falls. The gas given off is collected and tested.
   Explain why the reading on the balance slowly falls during the reaction.2 marks
3. Kofi, a student in Accra, makes copper(II) sulfate crystals. He warms 25 cm³ of dilute sulfuric acid, adds copper(II) oxide a spatula at a time while stirring, and keeps adding until some black solid remains undissolved. The solution turns blue. He filters the mixture, then heats the filtrate in an evaporating basin until all the water has gone. He obtains a small amount of pale blue powder instead of the large blue crystals he expected.
   Write a word equation for the reaction, and explain why Kofi adds copper(II) oxide until some remains undissolved.3 marks