Alka Seltzer Dissolving at Different Temperatures

Alka Seltzer Dissolving at Different Temperatures

The variable that I will change will be the temperature of the water

that the Alka Seltzer is put in.

For my results I will measure the time taken for the Alka seltzer

tablet to completely dissolve in water at different temperatures.

Input variables:

* Varying surface area of Alka-Seltzer tablet, i.e. if cut into

smaller pieces or crushed it will increase the surface area. (If

the surface area is increased (more powdered) the rate of reaction

also increases. This means that there are more collisions between

the solid and liquid.)

* Amount of tap water H2O used, i.e. volume (ml).

* Amount of Alka-Seltzer tablets used, i.e. quantity of tablets.

(one is used)

* Number of times the solution is stirred. (If the solution is

stirred more there are more collisions between the particles

therefore the reaction is speeded up.)

* Temperature of Water-°C. (As the temperature increases so does the

rate of reaction. By increasing the temperature, particles move

faster, i.e. they have more energy. So, they collide with more

energy and more frequently.)

* pH of Solution: Water has pH of 7 at 25°C. As the pH decreases,

i.e as the solution increases in acidity, the rate of the reaction

increases as well.

Output Variables:

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Rate of reaction depends on all the 6 points I have stated above:

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* If the surface area of the tablets is increased by crushing, the

particles around it in the solution will have more area to work

on, and the rates of reactions will increase because there will be

more collisions. Complete reaction will finish faster.

* The more amount of water used as we increase the temperature, the

quicker the tablets will dissolve because there will be more water

particles to collide with. So the rate increases.

* If the amount of tablets being used is increased for the same

amount of water, i.e as concentration increases, rate will

increase as well because there will be more collisions between

particles.

* If the water with Alka-Seltzer tablets are stirred during the

reaction, then the rates of reactions will increase because the

particles will be forced to make contact with each others and

react much quicker, rather than take their time to make contact,

and therefor...

... middle of paper ...

... water bath could have been used, because I could set it

to my required temperature. Also it would mean that the solution

inside it would reach the exact temperature or close to It., and not

increase or decrease once the water inside it has reached

equilibration.

It was also very difficult for me to observe exactly when the

Alka-Seltzer tablets had totally dissolved and consistently decide

this for every result obtained. This was probably the main factor that

would have decreased the accuracy of my readings. To avoid this

happening I would have needed to use specialized piece of equipment

which would tell me exactly when the tablet was dissolved

Overall, I can come to firm conclusion from my results that support my

prediction and background knowledge that: As the temperature

increases, less time will be required for a reaction to take place

i.e. the rate of reaction increases.

To improve the experiment overall I could use distilled water to avoid

inaccuracies related to the hardness of tap water. I believe I should

get a straight line curve.

Another improvement I could have made is to increase the range of the

temperatures investigated. (10°C to 100°C).