Types of chemical reactionIB MYP Sciences: Flashcards

Exam questions on Types of chemical reaction

1. In a school laboratory in Cairo, a student heats a spatula of green copper carbonate powder in a test tube using a Bunsen burner. After a few minutes the powder has turned black. A gas is given off that turns limewater cloudy. When the student stops heating, the reaction stops.
   Explain, using the observations, why this is a chemical change.2 marks
2. A student in Johannesburg places a clean iron nail in a beaker of blue copper sulfate solution. After 20 minutes the nail is coated with a pink-brown solid and the blue colour of the solution has become paler.
   Write a word equation for the reaction.2 marks
3. A student in Mexico City mixes 25 cm³ of dilute hydrochloric acid with 25 cm³ of dilute sodium hydroxide solution in a polystyrene cup. Both solutions start at 21.0 °C. After stirring, the highest temperature reached is 27.5 °C, and universal indicator added to the mixture turns green.
   Identify the type of reaction, name the two products and explain what the temperature rise shows.3 marks