Will a displacement reaction occur?

Transcription

1 Will a displacement reaction occur? Setting the scene The reactivity series lists metals in order of how reactive they are. More reactive metals are able to displace less reactive metals from their compounds. This is a displacement reaction. Aims In this practical you will: use the reactivity series to predict if displacement reactions will occur react different metals with different metal solutions and decide if a displacement reaction has occurred. You will be working scientifically to: use your knowledge of the reactivity series and displacement reactions to predict if a reaction will take place record your observations present observations using an appropriate table use your observations to decide if a displacement reaction has happened explain what has happened during the reactions, using equations to help do this. Safety Magnesium is flammable. Keep it away from naked flames. Lead foil is toxic and is hazardous to the environment. Dispose of it as directed by your teacher. Zinc nitrate is harmful and oxidising. Keep this away from sources of heat and wash any spills off your skin immediately. Magnesium nitrate is oxidising. Copper nitrate is harmful. Lead nitrate solution is toxic. Wear chemical splash-proof eye protection throughout the practical activity. If any chemicals get onto your skin, wash these off immediately and inform your teacher.

2 Equipment and materials eye protection magnesium pieces zinc pieces copper pieces lead pieces zinc nitrate solution magnesium nitrate solution copper nitrate solution lead nitrate solution test tubes or spotting tile test-tube rack pipettes Hypothesis Which of the following statements describes what happens if a displacement reaction takes place? a A less reactive metal will displace a more reactive metal from its compound. b A more reactive metal will displace a less reactive metal from its compound.

3 Prediction 1 Fill in the table below to show whether you think a displacement reaction will occur for each metal metal compound combination. Use ticks to show pairs you think will undergo displacement reactions and crosses to show those you think will not. Substance magnesium zinc copper lead magnesium nitrate zinc nitrate copper nitrate lead nitrate 2 Explain how you have made your predictions. Method 1 Place a small piece of your first metal into four separate test tubes. 2 Add 1 cm 3 of magnesium nitrate solution to one of the test tubes using a dropping pipette. Record your observations. 3 Repeat Step 2 using zinc nitrate, copper nitrate, and lead nitrate, using a clean test tube containing a fresh piece of metal and a clean pipette each time. 4 Now repeat Steps 1 3 for zinc, copper, and lead. Results Design a suitable results table to record your observations. Your results table should contain a space for recording observations for each metal reacting with each solution, as well as a way of showing whether displacement has occurred. Hint: use the prediction table above as a starting point.

4 Questions 1 List the metals you used in terms of their reactivity, starting with the most reactive. Use the mathematical symbol for more than to separate the metals in your list. 2 Identify which of the substances you have used are metals and which are metal compounds. Metals Metal compounds 3 Explain why it is not necessary to react a metal with a solution of its own compounds. For example, why is it not necessary to react copper with copper nitrate? 4 Write a word equation for each of the displacement reactions you observed occurring.

5 Extension 1 Explain, using particle diagrams, what happens during a displacement reaction. 2 Write a balanced formula equation for each displacement reaction you have identified in Question 4 above. Include state symbols in your equation. Choose from the following list of possible chemical formulae: Mg Mn Zr Zn Co Cu Pb Ph Mg(NO 3 ) 2 Mn(NO 3 ) 2 Zr(NO 3 ) 4 Zn(NO 3 ) 2 Co(NO 3 ) 2 Cu(NO 2 ) 2 Pb(NO 3 ) 2 Pb 3 (PO 4 ) 2