The purpose of this experiment is to analyze the rate of reaction and the different parametric quantities that affect it. In this experiment, we will be look intoing the consequence of temperature on the reaction between Sodium Thiosulphate and Hydrochloric Acid.
Theory:
Chemical reactions involve hits between reactant molecules or atoms to from bonds. For this, the molecules or atoms are required to come near to one another since new bonds can organize merely when the reactants are near plenty to portion negatrons or ease a transportation of negatrons. Collisions that lead to merchandises are referred to as effectual hits which consequences when the hits occur with adequate velocity energy and force to interrupt bonds of the reactants.
The minimal energy reactants need to possess to interrupt bonds and do a reaction is known as activation energy. Therefore there are two ways of increasing the rate of reaction:
increase the figure of hits
increase the sum of motion ( kinetic ) energy so that more hits lead to a reaction.
These depend on a figure of factors:
Size of atoms
Concentration
Temperature
Addition of a accelerator
Pressure of a gaseous reactant
This experiment trades with the consequence of one of these factors-concentration of reactants.
Increasing concentration, increases the chance of hits between the reactant as there are more of them available for interaction in the same sum of the solution mixture. Since the chance of the hits is higher, the chance of effectual hits increases excessively.
The purpose of this experiment to analyze and look into the consequence of this factor, on the rate of reaction between Na thiosulphate and hydrochloric acid.
The reaction between Na thiosulphate and hydrochloric acid returns to the undermentioned chemical equation:
Na2S2O3 ( aq ) + 2HCl ( aq ) A® 2NaCl ( aq ) + SO2 ( aq ) + H2O ( cubic decimeter ) + S ( s )
This equation can besides be represented in the ionic-equation signifier in the undermentioned mode:
S2O32- + 2H+ A® H2O + SO2 + S
The sulfur dioxide therefore formed is dissolved in H2O as sulfurous acid. The partly dissolved sulfur makes the solution turbid due to the formation of a colloid. Because of this, the solution turns more soiled and opaque as the liberated sulfur additions in measure. This belongings is used in the experiment to find the rate of the reaction.
Hypothesis:
It can be hypothesized that an addition in the concentration of the Na Thiosulphate would increase the rate of the reaction. Quantitatively, if the concentration of Na2S2O3 is increased by a factor of two, so the clip taken for the reaction to happen will lessening by a factor of two. This is tantamount to increasing the reaction rate by a factor of two.
Variables
Controlled: Factors like force per unit area, temperature, surface country of atoms and the proportion of atoms with regard to each other, that affect the rate of the reaction must be maintained.
Mugwump: Concentration of the reactants
Dependant: The rate of the reaction as the clip taken for the reaction to take topographic point would depend on the concentration.
Requirements:
Chemicals:
1 M Na thiosulfate solution
1 M HCl solution
distilled or deionized H2O
Equipment:
250-mL beakers
stirring rods
25-mL graduated cylinder
stop watch
Procedure
Prepare 5 beakers with different concentrations of Sodium Thiosulfate age-related macular degeneration Hydrochloric Acid by fixing 25ml solutions in the undermentioned mode:
Beaker
Number
Volume of
Sodium Thiosulfate
( milliliter )
Volume of
distilled or deionized H2O
( milliliter )
1
25
0
2
20
5
3
15
10
4
10
15
5
5
20
Make a little “ ten ” on a sheet of white paper with a pencil. Put the 1st beaker incorporating the Na thiosulfate solution over this “ ten ” and add 5 mL HCl solution and instantly get down clocking the reaction.
Stir the contents of the flask and enter the clip taken for the cross to be obscured by the sulfur precipitate formed and enter this clip in your informations tabular array.
Repeat this process for the staying samples.
Make a graph of the informations obtained by plotting the clip ( in sec ) for each reaction on the y-axis against the volume ( in milliliter ) of Na thiosulfate on the x-axis.
Data Collection:
S.No
Beaker No.
Volume of
Sodium Thiosulfate
( milliliter )
Volume of
distilled or deionized H2O
( milliliter )
Time / +0.01s
Chemical reaction Rate ( 1/t ) / +0.01s-1
1.
1
25
0
18
0.0560
2.
2
20
5
23
0.04340
3
3
15
10
31
0.03220
4.
4
10
15
56
0.02000
5.
5
5
20
112
0.00087
Data Presentation and Analysis
Datas Analysis:
The graph above corresponds to our hypothesis as the relation between the rate of reaction and the concentration of reactants is relative to the concentration of one peculiar reactant. This is due to the increased opportunities of fruitful hits ensuing in merchandises. in this instance, the reciprocal of the reaction clip, 1/time, is being used to mensurate the velocity of the reaction and represents how long it takes for a certain concentration of sulfur to organize when the hydrochloric acid is added to the Na Thiosulphate. The rate of reaction i.e. the clip taken for the reaction to happen therefore is seen to increase with an addition in the concentration of one of the reactants.
Restrictions:
The graph above is best fitted to our consequences which means that the experimental consequences had a grade of inaccuracy. This could hold been due to the undermentioned grounds:
Impurities in the reactants can impact the rate of reactions and inaccurate clip periods.
The least count of the measurement cylinder used to mensurate solution is 0.05cm3. the volumes measured are hence non precise. Due to this, the volumes of solutions measured might be inaccurate taking to inaccurate concentrations.
Since our research lab was air-conditioned, the reaction mixture could hold undergone uneven and sudden chilling.
The reaction clip when fillet and get downing the stop watch besides added to the inaccuracy particularly when the clip periods are truly little.
Alterations:
To get the better of the restrictions and give more accurate consequences, we can modify the experiment in the undermentioned ways:
A burette or a pipette could be more accurate in mensurating the volumes of solutions.
The experiment must be carried out at a distance from the air-conditioner to forestall rapid chilling of the solutions and keep a changeless temperature.
A purer solution can be made by utilizing better quality of the Na Thiosulphate.
Every person ‘s definition of the disappearing of the cross could be different. To get the better of this, an index could hold been used to bespeak the completion of reaction.
Precautions:
To minimise inaccuracy, the undermentioned safeguards were incorporated in the experiment:
The H2O bath is really hot and so the beaker with the hot acid must be handled excess carefully or it could be unsafe.
The acid must be handled with attention.
It is best that one individual clip during the whole of the reaction to cut down the mistake due to reaction clip.
Decision:
At the terminal of this experiment, it can be concluded that the concentration does hold an consequence on the clip taken for the reaction and accordingly on the rate of reaction. More specifically, an addition in concentration leads to an addition in the rate of reaction. The undermentioned decisions can hence be drawn:
Concentration Aµ / ____________ 1________________
clip taken for reaction to be complete
Concentration Aµ Rate of reaction
