SCH3U
The Reactivity of Metals
Purpose: To investigate and rank the reactivity of the following metals: lithium, sodium, potassium, magnesium,
calcium, zinc and copper.
Hypothesis: Based on what you have learned about the periodic trends (e.g. ionization energy, metallic character)
make a prediction about the relative reactivity of the metals listed above. Explain your reason(s) for this prediction.
Materials:
1000 mL beaker
dilute HCl (aq)
wire mat
test tubes
lab goggles
watch glass
test tube rack
phenolphthalein indicator
sodium
potassium
lithium
magnesium
zinc
copper
calcium
Pre-lab Questions:
1.
Classify each of the metals used in this lab into the following families:
a) alkali metals
b) alkaline earth metals
c) transition metals
2.
Complete the following general reaction forms:
metal + water
?
metal + acid
?
3.
Phenolphthalein is an acid / base indicator.
a) At what pH does this indicator turn pink? (see Chemistry 11 p. 412)
b) What type of solution (acidic or basic) does the pink colour indicate? (see p. 388)
4.
Read the procedure for part A and part B. Consider both the procedure and your predicted reactions from
question 2, what waste contained should be used for each section?
5.
Read the procedure below. Create a procedure (use a reference) and observations section in your
notebook, and create a blank observations table.
6. Safety
Review the provided MSDS sheets for each chemical or look them up on www.msdsforschools.ca.
Determine what appropriate safety equipment and procedures are appropriate, taking into account both the type
and amount of material being used.
Procedure:
Part 1 – Reaction with Water (* Note: Any metals that do not react in part 1 can be saved and used in Part 2.)
1.
Put 100 ml of tap water in a 1000 mL beaker.
2.
Place a piece of lithium on a watch glass.
3.
Carefully drop the metal into the beaker of water and immediately cover with the wire mat.
4.
Record your observations.
5.
If a reaction occurs, add 5 drops of phenolphthalein indicator to the solution. Record the colour of the
solution. If no reaction occurred, remove the metal.
6.
Dispose of the solution in the appropriate waste container and rinse the beaker.
7.
Repeat steps 2 to 6 using the remaining metals
Part 2 – Reaction with Hydrochloric Acid
1.
One quarter-fill a clean test-tube for each metal(s) that did not react in Part 1 with dilute hydrochloric acid.
2.
One at a time place each metal(s) that did not react in Part 1 into one of the test-tubes.
3.
Record your observations. Dispose of the solutions in the appropriate waste container.
4.
Rinse any unreacted metal with tap water and place in the fume hood to dry.
Observations: Record the observations in the table you designed.
Analysis:
1. For any reactions that occurred in Part 1 and Part 2, write the corresponding single displacement reaction. Be
sure to balance the chemical equations.
2. Rank the metals that reacted with water in Part 1 from most to least reactive.
(eg. X > Y >Z).
3. Rank the metals that reacted with acid in Part 2 from most to least reactive.
4. Which metals did not react with either water or acid?
5. Metals that react with cold water are more reactive than those that react with acid. With this in mind, create an
overall ranking of the metals from most to least reactive.
Conclusion: Restate the purpose and evaluate your hypothesis.
Discussion Questions:
1.
If one wanted to produce hydrogen gas and collect it for later use:
a) which of the reactions in Part 1 would be the safest?
b) which of the reactions in Part 2 would be the safest?
2.
a) Based on the results of the phenolphthalein test, what type of solution is produced when a metal reacts
with water?
b) Why was this test not performed in Part 2 (what problem would be encountered)?
3.
Metals react by losing electrons. Based on this fact, do very reactive metals have a high or low ionization
energy? Explain your response.
4.
a) Based on your results, are alkali metals or alkaline earth metals more reactive?
b) Explain your response to 4 a) by referring to the number of valence electrons and the ionization energy
of the elements found in these groups.
5.
a) Based on your results, are the most reactive metals found near the top or bottom of a group in the
periodic table?
b) Explain your response to 5 a) by referring to the number of occupied energy levels and the ionization
energy of the elements found in these groups.
6.
The ranking you created in this lab is called an activity series. The metal aluminum lies between magnesium
and zinc on the activity series.
a) Based on its location in the series, is the metal aluminum likely to react with water? If so, write a
balanced chemical equation.
b) Based on its location in the series, is the metal aluminum likely to react with hydrochloric acid? If so,
write a balanced chemical equation.