STTSS / Chemistry / S3 / Collaborative teachingp.1

SHATIN TSUNG TSIN SECONDARY SCHOOL (2005-2006)

Collaborative teaching

Subject: / Chemistry
Class: / S.3D
Date: / April 27, 2006
Topic: / Metal reactivity series
Duration: / 80 minutes
Pre-requisites: / Students are able to
  1. state the products of different reactions of metals.

Instructional
Objectives: / After this lesson, students should be able to
  1. compare the rate of reaction from observations;
  2. arrange the reactivity of metals according to their rates of reaction.
  3. write word equations for different reactions of metals.

H.O.T. skills: / Comparison, prediction
Time / Plan / Remarks
1 / 0-15 / Introduction
(T) / The ear ring of Ms Mak. Some say that cheap necklace would cause allergy to the skin while pure gold or silver would not. Do you have this experience? Why?
(S) / Give explanation e.g. impure materials cause allergy and etc.
(T) / Ask about the chemical properties of metals.
(T) / Ask what to do if we want to investigate thechemical properties of metals (or a substance).
(S) / Suggest experiment e.g. (1) heat in air, (2) put in water, and (3) put in acid.
(T) / Ask if they would show similar properties.
(T) / Ask if there are any differences in their rates.
2 / 15-35 /

Do experiments for heating metals in air

(T) / Give experiment worksheet to students.
(S) / Read procedure for heating metals in air.
(T) / Remind students about safety precautions, e.g. put on goggles, stand away when heating calcium, don’t look directly when heating magnesium
(S) / Do experiment and write results on the blackboard.
(T) / Ask questions for discussion.
Key questions:
  1. How can we make the test fair?
  2. What should we observe when comparing their rates?
  3. Not all metals (e.g sodium, potassium, zinc, aluminium and lead) are used in this experiment. Suggest reasons.
  4. We have to clean the metals before experiment. Why?
  5. It takes about one minutes before calcium reacts with air. Why?
  6. What is actually produced? (Hint: give the elements that are present in the chemicals.)
/

Worksheet x42

Metals (calcium granule x10, magnesium ribbon x10, iron wool x 1 bottle, copper foil x8)
Tongs x10
3 / 35-65 /

Do experiments for putting metals into water and acid

(S) / Read procedure for putting metals into water and acid.
(S) / Remind students about safety precautions, e.g. acid may spray out when putting metals into it.
(T) / Instruct students to do reactions with either (1) water or (2) acid.
(S) / Do experiment and write results on the blackboard.
(T) / Ask questions for discussion.
Key questions:
  1. How can we make the test fair?
  2. What should we observe when comparing the rates?
  3. Aluminium reacts only after a few minutes. Give reason.
  4. Is it possible to compare reactivity by counting when metals start to react?
  5. What is actually produced? (Hint: give the elements that are present in the chemicals.)
/

Metals (calcium granule x10, magnesium powder x1, aluminium powder x1, zinc powder x1, iron powder x1, lead powder x1, copper turning x1)

2M hydrochloric acid x10
4 / 65-80 /

Discussion of results

(S) / Discuss and arrange the order based on results.
(S) / Explain their arrangements.
(T) / Give the reactivity series for 13 metals:
K, Na, Ca, Mg, Al, Zn, Fe, Pb, Cu, Hg, Ag, Pt, Au
Key questions:
How can we arrange the order of metals under copper?