Word processing lesson plan

My Word Processing Lesson Plan

DATE: 15^th October 2007

CLASS: Form 4

TIME: (2) periods (120 minutes).

UNIT: Rate of reactions.

TOPIC: Effect of concentration on the rate of a chemical reaction.

REFERENCES CXC Module No. 5 Chemistry for CXC- Mohommed.

Perquisites Knowledge: students should - Understand the concept of Concentration - Know how to construct graphs and interpret straight line digraphs. - Possess knowledge of the Haber process and Contact process. - Possess basic computer literacy skills which include use of word processing, and spreadsheet. Skill: students should know how to (1) Draw graphs using appropriate scales. (2) Perform simple measurements using the measuring cylinder.

MATERIALS & RESOURCES FOR TEACHER FOR EACH GROUP/STUDENT (1) Over Head Projector (2) Hydrogen peroxide (1M) and Manganese (iv) Oxide (3) Magnesium ribbon and Sulphuric acid (1M). (1) 350 ml of sodium thiosulphate (0.1 M) (2) 350 ml of sulphuric acid (0.1 M ) (3) 5 Beakers, 3 measuring cylinders (4) Distilled water

CONCEPT: Rate of reactions: Chemical reactions occur at different rates. Certain factors either speed up or slow down the rate of a chemical reaction. Concentration is one such factor.

OBJECTIVES At the end of the lesson, students will be able to: (1) Define the term Rate of a chemical reaction. (2) List factors affecting the rate of a chemical reaction (3) Discuss the effect of varying concentration on the rate of a chemical reaction (4) Relate increase in pressure to increase in concentration (5) Appreciate that increase in pressure or concentration has industrial implications. Classification Knowledge Knowledge Application Application Affective

PROCESS SKILLS During this lesson, student will be engaged in: Identifying/formulating a problem Designing and Planning an experimental procedure Setting up and executing experimental work Observing and measuring Recording data and observations Interpreting and evaluating data and observations[a1] Communicating scientific ideas, observations and arguments Applying scientific ideas and methods to solve qualitative and quantitative problems Decision-making based on examination of evidence and arguments X
ACTIVITIES Introduction: Students (Ss) are asked to identify the differences between two chemical reactions demonstrated by the teacher (Tt). These reactions are: (1) The reaction between Manganese (iv) oxide and Hydrogen peroxide. (2) The reaction of a 5 cm long magnesium ribbon with 0.1 mol dm-3 sulphuric acid solution. Development: Tt performs two simple chemical reactions and Ss are asked to identify the differences between them. Tt focuses on (how fast or how slow) rate and asks Ss to define rate. Ss are asked to explain why rate studies are important. Tt emphasizes the importance of rate studies in (a) the Haber process and (b) the Contact process (c) the freezing point of meat and (d) the decomposition of hydrogen peroxide. Ss are asked to identify the factors affecting rate of a chemical reaction. Ss are asked to perform an experiment to investigate the effect of concentration changes on the rate of the reaction between sodium thiosulphate and hydrogen peroxide. Ss asked to construct a table using the computer to display their results. Ss draw a graph of 1/T versus volume of Na2S2O3 using the computer. Ss are asked to comment on the shape and the information the graph shows. Ss then attempt to explain why increasing concentration increases the rate of the chemical reaction. Tt establishes relationship between concentration and pressure. Tt asks Ss to explain the implications of increasing concentration/ pressure on industrial processes. Tt and Ss summarizes lesson. CONSOLIDATION: (1) Ss are asked to do three questions on assessment sheet. (2) Using Microsoft word, write your discussion of this laboratory exercise using the guiding outlined in your assessment sheets.
TEACHER’S REFLECTIONS:

The following are the slides that are to be presented on power point as a teaching aid.

The rate of a chemical reaction is defined as:

(1) The rate of consumption of reactants

or (2) The rate of formation of products.

In simple terms, it is defined as:

The amount of product formed

Time taken

Why Study Rate?

(1) It gives an indication as to how slow or how quickly a reaction will proceed.

(2) It enables us to get an indication as to the amount of money that can be generated industrially.

(3) It allows us to know the shelf life of products.

Examples include:

(1) Temperature

(2) Catalyst

(3) Surface area

(4) Light

(5) Pressure

(6) Concentration

Our focus today is on the effect of concentration on the rate of a chemical reaction.

(1) Increasing concentration increases the number of molecules in a given volume.

(2) The chances of the particles colliding increase; i.e. they collide more frequently.

(3) When they collide, bonds are broken and products are formed.

(4) Therefore, increasing the thiosulphate concentration increases the rate of the reaction.

* Concentration is inversely proportional to volume.

* Increase in pressure leads to a decrease in volume.

* A decrease in volume means that there are more molecules in a smaller volume.

* Hence rate of the reaction increases.

Students are to follow instructions carefully and carry out this experiment.

The teacher goes through the details paying attention to safety in the laboratory.

Experiment- The Disappearing Cross.

When sulphuric acid reacts with sodium thiosulphate, a cloudy suspension of sulphur is formed. This cloudy suspension of sulphur scatters light and as such it makes the solution opaque.

quation: S₂O₃^2- (aq) + H⁺ (aq) → S (s) + SO₂ (aq) + H₂O (l)

Procedure:

(1) Using a measuring cylinder, place 50 cm³ of a 0.1 mol dm^-3 sodium thiosulphate solution into a beaker.

(2) Add 50cm³ of a 0.5 mol dm ^-3 sulphuric acid, noting the time you do so with the stopwatch provided.

(3) Place the beaker over the cross on the paper provided and record the time taken for the x to disappear.

(4) Repeat the above steps using the different volumes of each solution in the table provided.

You are also required to construct your own table using Microsoft word and insert all the missing data. This includes your experimental results, calculation of 1/T, and the concentration of the sodium thiosulphate solution.

Table showing results of the reaction between thiosulphate and acid.

Experiment	Volume of acid	Vol. of Na2S2O3	Vol. of water	Time (s)	1/T	Concentration/mol
1	50	50	0
2	50	45	5
3	50	40	10
4	50	35	15
5	50	30	20
6	50	25	25
7	50	20	30

(1) Plot a graph of 1/T versus volume of sodium thiosulphate using Microsoft excel and import the graph into your document. Your graph should be a straight line graph.

Assessment.

Using Microsoft office, write your discussion of this laboratory exercise using the following questions as a guide.

(1) What does the term “rate of a chemical reaction” refer to?

(2) List some factors using bullets that can affect the rate of a reaction.

(3) Using your graph, explain how an increase in concentration affects the rate of a chemical reaction at the atomic level.

(4) Using the internet, locate three diagrams or models that can be used to illustrate the effect of concentration on the rate of a reaction. Choose one and import it into your word document.

Product expected from students

(1) Table displaying results.

(2) Graph drawn using Microsoft excel.

(3) The experimental discussion.

(4) The diagrammatic representation obtained from the internet.

Table showing results of the reaction between thiosulphate and acid.

Experiment	Vol.of acid	Vol. of Na2S2O3	Vol. of water	Time (s)	1/T	Concentration/mol *10-3
1	50	50	0	40	0.025	5
2	50	45	5	46	0.022	4.5
3	50	40	10	53	0.019	4.0
4	50	35	15	59	0.017	3.5
5	50	30	20	77	0.013	3.0
6	50	25	25	91	0.011	2.5
7	50	20	30	120	0.008	2.0

Discussion

The rate of a chemical reaction is defined as the rate of consumption of a reactant or the rate of formation of a product. There are many factors that affect the rate of a chemical reaction such as

· Temperature

· Catalyst

· Surface area

· Light

· Pressure

· Concentration

In the above experiment our inquiry was based on investigating the effect of increasing concentration on the rate of a chemical reaction. The reaction between sodium thiosulphate and sulphuric acid results in the precipitation of solid sulphur which makes the solution opaque and obscures the view of the cross at the bottom of the beaker. The faster the sulphur is formed the faster the cross will disappear. Hence the time taken for the cross to disappear is an indication of the rate of formation of the product (sulphur).

From the graph it can be seen that as the concentration of sodium thiosulphate increases the reaction rate increases proportionally. From this experiment it can be inferred that increasing the concentration of a reactant results in an increase in the rate of the reaction. This is captured in the following values. When the concentration of the sodium thiosulphate is 2.0 *10^-3 moles, the rate is 0.008 moles dm^-3 s^-1; however when the concentration increases to 5 * 10^-3 moles of sodium thiosulphate, rate increases to 0.025 mol dm^-3 s^-1. This explanation can be shown in the annotated diagrams below which are adapted from the website quoted below. In this example however calcium carbonate (marble chips) is reacted with acid.

=>

=>

http://www.wpbschoolhouse.btinternet.co.uk/page03/3_31rates.htm.

Retrieved 10^th October 2007.

Rationale for the incorporation of ICT into Lesson

It is intended that the incorporation of ICT in this laboratory inquiry will allow for the development of skills to:

(1) Construct tables using word processing

(2) Constructing graphs in Microsoft excel and importing it into a word document.

(3) Accessing information from the internet.

(4) Produce a laboratory report in word paying particular attention to:

(a) Title/Heading

(b) Paragraphing

(c) Grammar

(d) Spelling and spell checks

(e) Using bullets to highlight points

(f) Justification

(g) Triangulation – To judge the quality of sources and select “reliable and unreliable information”. This is done by allowing students to view three diagrams or models which help to explain the effect of concentration on the rate of a chemical reaction and selecting one based on their judgment using theory to ground their selection.

(h) Students will also need to quote suitable sources of information.

The objectives outlined above spans different levels of Bloom’s Taxonomy. These range from knowledge as in spell checking to evaluation and judging models and diagrams found on the internet based on prior knowledge.

The End.

---

[a1]This HOT skill is not reflected in your learning objectives.