CHAPTER 17 – COMPOUNDS, MIXTURES AND SEPARATION OF MIXTURES
Summary questions 1. Outline the difference between a compound and a mixture.
2. Answer questions a.–d. for each of the models (1–3) shown in Fig. 17.13. 1
2 3
:Fig. 17.13
a. How many atoms are present in the model? b. How many different types of atom are present in the model? c. Is this model representative of an element, compound or mixture? Explain your answer. d. Which model shows an example of molecules?
3. Table salt (sodium chloride) is made up of the elements sodium and chlorine. Sodium is a very reactive metal and chlorine is a poisonous gas with a distinctive odour. Why does salt not smell, poison you or fizz in your mouth?
4. Draw four diagrams to show: a. a mixture of three elements b. a compound c. an element d. a mixture of two compounds
5. Rock salt is salt found in the ground. It contains particles of salt mixed with sand and other rocks. Develop a method for how you might obtain a pure sample of dry salt from the rock salt. Draw a diagram of the investigation set-up you would use.
:Fig. 17.14
6. Suggest a method for separating the following mixtures and list the piece(s) of equipment y would need to carry out the separation.
Mixture
Salt and sand Alcohol and water Salt and water Coloured ink in a pen
Separation technique Equipment needed ece(s) of equipment you