Ratess Of Reaction Essay, Research Paper

Contentss Page

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Page Title

1 Planning

2 Method and anticipation

3 Diagram

4 Consequences for temperature and concentration on Tables

5 Graph for consequences for rate of reaction against temperature

6 Graph of consequences for rate of reaction against clip

7 Graph for concentration consequences

8 Graph and tabular array of typical consequences

9 Conclusion and Evaluation & # 8230 ;

10 End of rating

This probe is about Ratess of Reaction and what affects them. In this instance I am traveling to look at hydrochloric acid and Na thiosulphate, which is a precipitation reaction. I will be look intoing whether a alteration in temperature affects the rate of reaction.

( Planing )

Sodium thiosulphate and hydrochloric acid respond together to bring forth Na chloride, sulfur dioxide, H2O and sulfur. This is besides shown in the word and symbol equations below:

Word:

Sodium thiosulphate + Hydrochloric acid? Sodium chloride + sulfur dioxide + H2O + sulfur

Symbol:

Na2S2O3 ( aq ) + 2HCl ( aq ) -* 2NaCl ( aq ) + S ( s ) + SO2 ( g ) + H2O ( cubic decimeter )

Both of these solutions are colorless. They react to bring forth a solid ( sulfur, which is the xanthous precipitate ) , and as it can non fade out in H2O, the solution will go cloudy.

A reaction will merely happen where the atoms of the reactants meet and combine. This is called the hit theory. Therefore it stands to ground that to increase the rate of reaction it is necessary to do more atoms to clash harder and do it go on more frequently. There are several ways to make this and these make up the variables for this experiment.

1 ) Increasing the temperature & # 8212 ; Increasing the temperature of the reactants will supply the atoms with more kinetic ( motion ) energy. This will do the atoms move faster. The figure of successful hits per second will besides increase ; hence the rate of the reaction increases. More hits have an energy greater than the activation energy. But, although the rate of reaction is increased, the sum of the merchandises produced at the terminal will stay the same ( this is a uninterrupted, independent variable, which I will be proving ) .

2 ) Adding a accelerator & # 8212 ; a positive accelerator will rush up a reaction. The accelerator provides surfaces, which the molecules stick to, and respond upon. It besides lowers the activation energy, which is the energy needed for bonds to be broken, and the reaction to happen ) by cut downing the initial energy needed. This increases the figure of successful hits, ensuing in an increased rate of reaction. Catalysts are specific to certain reactions.

3 ) Increasing the surface country & # 8212 ; This involves? interrupting up? the reactant into smaller pieces. It provides more chances for the atoms to clash ( for illustration, the reaction between Ca carbonate and hydrochloric acid. When the Ca carbonate is powdered, there is more of it in contact with the hydrochloric acid ) . In some instances, stirring besides has the same affect.

4 ) Increasing the concentration & # 8212 ; A more concentrated solution will incorporate more of the same atoms, which will be more tightly packed. So, one time once more, there will be a much greater opportunity of successful hits between the atoms ( In this instance, this reaction is exothermal, as it gives out energy )

( Method )

I will be utilizing:

A boiler

A beaker

A thermometer

A timer

Sodium thiosulphate

Hydrochloric acid

A conelike flask

A piece of paper

A black marker

A window ( as a light beginning )

A pipette

I shall put up the equipment as in the diagram on page 3, pulling a black cross on a piece of paper with the marker. I shall so make full the boiler with H2O, and heat the H2O, to the testing temperatures. I will put the 5cm? of Hydrochloric acid into a 50ml conelike flask. When the temperature is right ( 20, 30, 40, 50 and 60 grades centigrade ) , I shall so add 25cm? of a mixture of Na thiosulphate and H2O ( the concentration of the Na thiosulphate will be 0.25 grinders, and this will stay changeless during the experiment ) . Simultaneously, I will get down the timer. I shall prove each temperature two times and so take an norm to guarantee that the consequence is balanced and non merely a consequence of a good luck. The consequences will be taken optically, as we do non hold the opportunity to utilize a computing machine. I will maintain the timer on until the black cross marked on the piece of paper has disappeared. To guarantee my consequences are every bit accurate as possible, we will utilize a pipette to mensurate the Na thiosulphate, when puting it in the beaker. I will seek to maintain my measurings every bit precise as possible.

( My Diagram for the experiment is on Page 3 )

I will hold to see safety safeguards, so I will have on goggles, and bind my hair back to forestall any jeopardies. I will besides hold to do certain the setup is stable.

I will obtain consequences from the other pick of experiments, which is on the variable of concentration.

I will besides obtain? typical consequences? , to compare my consequences.

( Prediction )

I predict that temperature is relative to rate of reaction. I say this due to my research on the hit theory, etc. If the temperature is increased, the rate of reaction will besides increase, as the atoms will be given more energy. The rate of reaction will duplicate each clip the temperature is increased by 10? C ( which is what happens harmonizing to my typical consequences, and harmonizing to more information given to me by my instructor ) . Besides, for the consequences I will obtain for the concentration experiment, I predict, as the concentration is increased, the rate of reaction will increase. Finally, I predict that the stronger reaction will be that of temperature as at a higher temperature, there will be more parti

cles clashing with adequate energy to do the reaction happen ; the activation energy.

( Consequences )

Below are my consequences for the experiment.

Temperature ( ? C ) Concentration of the Na thiosulphate solution

Thiosulphate Volume of Na2S2O3 and H2O Volume of Acid

( cm? ) Time ( 1 ) for cross to go obscured

Time ( 2 ) for the cross to go obscured Average Rate of reaction

1/t ( /s )

20 0.25 m 25 5 94.6 87.9 91.24 0.0110s

30 0.25 m 25 5 74.2 59.4 63.86 0.0157s

40 0.25 m 25 5 19.57s 20.72s 20.15s 0.051s

50 0.25 m 25 5 19.10s 16.72s 17.5 0.056s

60 0.25 m 25 5 12.0 11.4 11.5 0.087s

( The graphs for these consequences are on pages 5 and 6 )

These are the consequences for fellow student Jugal Patel, who completed the experiment for concentration, and how it affects the rate of reaction.

Volume of

Na2S2O3

solution ( cm? )

Volume of H2O Concentration of

Na2S2O3

Volume of acid

( cm? ) Time ( 1 ) for cross to go obscured Time ( 2 ) for the cross to go obscured Average Rate of reaction 1/t ( /s )

50 0 0.15m 5 53.48s 56.03s 54.76s 0.018s

40 10 0.12m 5 63.21s 65.42s 64.32s 0.0156s

30 20 0.09m 5 108.00s 103.47s 105.79s 0.009s

20 30 0.06m 5 154.36s 153.09s 153.73s 0.0065s

10 40 0.03m 5 350.07s 348.59s 349.33s 0.0029s

( And for comparing, a graph for these consequences is on page 7 )

( Decision )

Upon looking at my consequences and graph, I do non see a clear form emerging. Mentioning back to the secondary grounds of typical consequences, I see what should hold occurred ( this is on page 8 ) . My consequences do non turn out my anticipation, precisely, either. I said the consequences would be relative, which was correct. However, I besides said the rate of reaction will duplicate as the temperature is increased by 10? C. This is because the atoms of the reactant will be provided more kinetic energy, hence, they will travel faster, doing the rate of reaction to rush up. This is non confirmed by my consequences. At 20? C and 30? C, the rate of reaction seems to increase reasonably steadily. But one time we went up to 40? C, the rate of reaction increased dramtically from 0.0157s to 0.51s. A human or experimental mistake must hold caused this to go on. At 50? C, the rise seems to be steady once more, traveling from 0.51s to 0.56s. Acording to my anticipation, and my typical consequences, this rise in rate of reaction is really little, at this phase. And at 60? C, the rate of reaction is 0.87s, which seems to be excessively high the temperature. My anticipation that temperature would be the quicker rate of reaction was right. Comparing Jugal? s consequences to my consequences, I can see that the rate of reaction utilizing the highest concentration was merely 0.18, compared to 0.87. This steeper graph can be explained by stating that were plentifulness of both reactants in the solutions tested. Faster hits will merely happen when the temperature is increased. In fact there was plenty to back up a much faster reaction than the one, which occurred. Because there were adequate atoms, the most of import factor became the activation energy. By 40? many of the atoms had reached activation energy. They so gave out heat themselves and so speeded up the reaction doing the big addition after 40? . However the hit theory can still be applied to both variables because when temperature/concentration additions, so does reaction rate. We used 0.25 grinders of the Na thiosulphate, and the highest concentration of the Na thiosulphate was 0.15, which is contains a batch less atoms.

( Evaluation )

No, non all my consequences were accurate. There are many? unusual? consequences in my experiment. This could wholly be blamed by human mistake and experimental mistake. Although during the experiment we were non cognizant of the mistakes, they have shown up rather clearly now. The method we used, could be improved by taking quite a figure of steps. Below, I have listed what I think has been done? incorrect? , and what could be done to better it if I repeat the experiment:

The temperature of the Na thiosulphate was non measured. The colder acid may hold bought down the temperature of the hydrochloric acid.

We conducted the experiment near window, and used natural visible radiation. This may besides hold affected the experiment as clouds were continually go throughing over the Sun. An unreal beginning of visible radiation would hold been more accurate.

We used a thermometer to mensurate the temperature. It would hold been more accurate to utilize a H2O bath.

We could besides hold washed out the glass points really exhaustively, as foreign ions may hold been present, and these may hold damaged the consequences.

To be able to compare the concentration and temperature even further, we should besides hold used 0.15 grinders of Na thiosulphate. This would hold made the trial fairer.

I personally wear? t think that we gained a just mean. We planned to reiterate each one 3 times, but during the first lesson, but we realised we wouldn? Ts have adequate clip to finish each experiment three times, so we had to restrict it to two. Had we non made all the experimental mistakes I have listed above, we may hold had more accurate consequences.

If I were able to widen my consequences, I would execute the experiment once more, doing all the accommodations mentioned above. I would besides:

1 ) Do an experiment for concentration, as from the consequences I have I can non state whether they have been made up or non.

2 ) For the temperature experiments, I would utilize data-logging to be highly accurate.

3 ) And one time once more for temperature, I would make the experiment up to 80? , to widen the consequences. If it had been possible to prove 80? on the computing machine, I might be able to see the temperature at which all of the atoms have reacted and the reaction Michigans

4 ) Finally, I would seek adding a suited accelerator if there is one to utilize.

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