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End of chapter exercises

Physical and chemical change

Textbook Exercise 13.3

For each of the following definitions give one word or term:

  1. A change that can be seen or felt, where the particles involved are not broken up in any way

  2. The formation of new substances in a chemical reaction

  3. A reaction where a new product is formed from elements or smaller compounds

Solution not yet available

Explain how a chemical change differs from a physical change.

Solution not yet available

Complete the following table by saying whether each of the descriptions is an example of a physical or chemical change:


Physical or chemical

hot and cold water mix together

milk turns sour

a car starts to rust

food digests in the stomach

alcohol disappears when it is placed on your skin

warming food in a microwave

separating sand and gravel

fireworks exploding

Solution not yet available

For each of the following reactions, say whether it is an example of a synthesis or decomposition reaction:

  1. \((\text{NH}_{4})_{2}\text{CO}_{3} \rightarrow \text{NH}_{3} + \text{CO}_{2} + \text{H}_{2}\text{O}\)

  2. \(\text{N}_{2}\text{(g)} + 3\text{H}_{2}\text{(g)} \rightarrow 2\text{NH}_{3}\text{(g)}\)

  3. \(\text{CaCO}_{3} \rightarrow \text{CaO} + \text{CO}_{2}\)

Solution not yet available

For the following equation: \(\text{CaCO}_{3}\text{(s)} \rightarrow \text{CaO (s)} + \text{CO}_{2}\text{(g)}\) show that the law of conservation of mass applies. Draw sub-microscopic diagrams to represent this reaction.

Solution not yet available