Universiti Pendidikan Sultan Idris

UNIVERSITI PENDIDIKAN SULTAN IDRIS

TKU 3023 INFORMATION TECHNOLOGY AND COMMUNICATION IN CHEMISTRY

ASSIGNMENT : SPREADSHEET

TITLE : EFFECT OF CONCENTRATION ON THE RATE OF REACTION

NAME

MATRIC NUMBER

NOOR ZATILAKHMA BT DANI

D20081032322

NUR SAHIDA BT MAT HUSIN

D20081032326

GROUP : B ( THURSDAY- 1P.M-4P.M) LECTURER’S NAME : MISS ASMAYATI BINTI YAHAYA DATE OF SUBMITTED : 8 th SEPTEMBER 2009 EFFECT OF CONCENTRATION ON THE RATE OF REACTION

Teacher’s Guide / Chemistry Form 5

SCIENTIFIC CONCEPT

The reaction rate for a reactant or product in a particular reaction is intuitively defined as how fast a reaction takes place. Concentration of reactant is one of the factors that can affect the rate of reaction. Concentration is the measure of how much of a given substance there is mixed with another substance. Reaction rate increases with concentration because the increasing numbers of reactant molecule that will be react with another reactant. As the number of reactant molecule increase, the frequency of collision between the reactant molecule is increase. As a result, the frequency of effective collision also will be increase. Effective collision is the collision that can cause the reaction to occur and the new product will be produce. So, if the reactant with high concentration is used, the rate of reaction will increase. The effect of concentration can be determined by first recording the time taken for the reaction to occur then calculating the 1 / t using the formula.

Experiment

1

2

3

4

5

Concentration of Na2S2O3, M1V1/V2(moldm-3)

0.2

0.16

0.12

0.08

0.04

Time, t(s)

24

30

42

62

111

1/Time, 1/t(s-1)

0.041

0.033

0.024

0.016

0.009

UNIQUE FEATURE OF THIS ACTIVITY This activity requires the student to calculate the rate of reaction by using formula. The unique feature of using spreadsheets are:  The ability to tabulate data and assists students to calculate answers. This allows the removal of drudgery and tedious calculation. The data can be manipulated easily, for instance if the time taken for ‘X’ to disappear is changed, the 1/ t can be calculated.

 Data displayed in a systematic manner, save time in drawing graphs, show relationship of different concentration of reactant against time.

 Students will discover that a spreadsheet can be used to process data.

 Students are allowed to do more important things such as analyzing the data or the graph.

ENGAGE

The power of salt

SALT FISH

1. What the effect of using high concentration of salt solution compare using water solution on the time taken for the fish to dry ? 2. How the concentration of solution can affect the rate of reaction ?

EMPOWER

1. Students plan an experiment to observe the effect of concentration of reactant on the rate of reaction. 2. The students are given the following apparatus:  Measuring cylinder  Conical flask  Stopwatch  A piece of white paper marked ‘X’ at the center  Sodium thiosulphate solution  Sulphuric acid  Distilled water 3. Students have constructed a hypothesis before doing the experiment. 4. Students should know the effect of concentration on the reaction rate. 5. Students have to determine the variables involved. 6. The procedures of conducting the experiment are discussed. 7. Using the formula of Rate of reaction =

1_________________ Time taken for ‘X’ mark to disappear

* Students are able to find the rate of reaction using spreadsheet program

How to set up the spreadsheet 1. Insert the data that obtain from the experiment to the table 2. Insert the border into the table

How to draw a graph with the spreadsheet 1. Select a line graph 2. Highlight C4 to G5, click ‘Series’, this will draw a line graph base the data from the

highlight area that is concentration versus time taken. 3. Click ‘category (x) axis’, then highlight C5 to G5 ( this will show the actual scale of xaxis according to the data) then click ‘Next’. 4. Name the chart. 5. Label the x- axis and y- axis as concentration and time taken. 6. Apply the same step to draw the second graph, concentration versus 1/time.

Questions 1. Based on plotted graph, explain the effect of concentration of sodium thiosulphate on

each of the following a) Time taken for the ‘X’ mark to disappear from view. b) Rate of reaction 2. What the meaning of the ‘ time taken for ‘X’ mark to disappear recorded’? 3. Why must the size and shape of conical flask used in all the experiments be of the same size and shape?

Answer: 1. a) Based on the graph, as the concentration of sodium thiosulphate solution increases, the time taken for ‘X’ mark to disappear from view is decreases. b) As the concentration of sodium thiosulphate solution increases, the rate of Reaction also increases.

2. The meaning of the ‘time taken for ‘X’ mark disappear recorded’ id referred to the time taken for the constant mass of sulphur formed. 3. The size and shape of conical flask used in all the experiments must be of the same size and shape because to ensure the mass of sulphur precipitates formed were of the same mass.

ENHANCE

In the process of latex vulcanization, we need to use formic acid in suitable concentration. Which is the most suitable concentration of latex solution for molecules of formic acids to react

with molecules of latex more faster? What happen to the solution of latex when we add the formic acid into latex solution with different concentration?

Answer: The modest concentration of formic acid is with pH=4 because this pH is the most suitable acid used for vulcanization of latex. For example, two solution of latex is prepared which both of the latex has different concentration of latex. In solution A the latex concentration is 20% while in solution B the latex concentration is 5%. When we add the same amount of formic acid that is 5 ml into both of the solution, we can see latex vulcanization in the solution A occur more faster compare to the solution B. This is because the high concentration of solution A caused the molecules of formic acids to react with molecules of

latex more faster. So, when the

concentration increase, the rate of reaction also increase. Thus, the rate of reaction in solution A is faster. However the latex vulcanization in this solution is imbalance because when the suitable concentration of acid added into latex solution, not all the acids react with latex solution. That’s why the latex vulcanization is imbalance.