Explore what happens to atoms and molecules when new materials are made in chemical reactions, using this lesson plan with activities for 11–14 year olds Show
In this practical activity students explore their ideas about what happens to atoms and molecules when new materials are made during a chemical reaction. They follow this up by using ball and stick models to explain their observations. These models are the ‘prop’ to focus student thinking and discussion about chemical reactions. Learning objectivesStudents will be able to:
Sequence of activitiesDemonstration and introduction
Practical 1Organise students into groups of three and give each student an ‘Activity sheet’. Support and supervise as students:
Ask students to explain to their group what they have seen in terms of particles and write this on their ‘Activity sheet’. Plenary 1
Practical 2: planningSupport the students as they:
Be sure to check on safety issues. Practical 2Supervise students as they carry out their experiment:
Plenary 2
ModellingIntroduce ball and spoke models. Circulate and support with prompts while student groups:
Before finishingProvide a final opportunity for students to add to and modify their explanations about what happens when the solutions mix. FeedbackCollect in student sheets and add comments to identify achievement. Ask questions to help students focus on the areas they need to develop. CommentaryThe initial demonstration gives substance to the purpose of the session. Although simple, using ‘traffic lights’ forces students to think for themselves. The ideas they develop are then extended as they listen to the ideas of other students. The group work, both in the experiment and in the modelling exercise, is creative and evaluative; it encourages thinking, which leads to learning. By reviewing the worksheet, the teacher can see how much each student has moved forward and so address their individual needs in the feedback. Practical notesEquipmentFor experimental work:
Other equipment:
Health, safety and practical notes
Answers
A possible experimental method is to put one solution in an ignition tube and the other solution in the conical flask. The ignition tube is held by a cotton thread trapped by a cork in the mouth of the conical flask so that it does not become horizontal. This arrangement is weighed. The thread is released by loosening the cork to allow the ignition tube to become horizontal and for the two solutions to mix. The equipment is weighed again. The two masses are the same showing that there is no change of mass when new substances are formed in a chemical reaction. Additional informationThis lesson plan was originally part of the Assessment for Learning website, published in 2008. Assessment for Learning is an effective way of actively involving students in their learning. Each session plan comes with suggestions about how to organise activities and worksheets that may be used with students. Acknowledgement V. Barker, Beyond Appearances: Student’s misconceptions about basic chemical ideas: A report prepared for The Royal Society of Chemistry, London, section 5.4 Teaching about chemical reactions. London: Royal Society of Chemistry, 2000. What colour does lead nitrate react with potassium iodide?Lead nitrate reacts with potassium iodide to form a yellow precipitate of .
What is the colour of lead nitrate and potassium nitrate?Explanation: Lead nitrate and potassium iodide; both are colourless.
What happen when lead nitrate reacts with potassium iodide?When a solution of potassium iodide is added to a solution of lead nitrate taken in a test tube, the precipitation of a yellowish solid is observed. This yellowish solid is lead iodide. Potassium nitrate is formed along with lead iodide. This is a double displacement reaction.
What is the colour of lead nitrate?Lead nitrate is a white crystalline solid. The material is soluble in water.
What is the colour of potassium iodide?It is a white salt, which is the most commercially significant iodide compound, with approximately 37,000 tons produced in 1985. It absorbs water less readily than sodium iodide, making it easier to work with.
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