Introduction:

So basically, in science class, we have been doing an experiment using vitamin C tablets to see the chemical reactions. It could have been nice if we used the alkali metals but since that was too challenging, we used the safe vitamin C tablets. We were trying to see the reactions that the tablets have when they touch the water in the beaker and to see how fast they react until they are fully dissolved into the solvent. Just like the vitamin C tablets produce gases in the water, the alkali metals also do that and as it goes down like cesium from Lithium, they kind of like explode which is very dangerous. They must be stored under oil in sealed containers to prevent violent reactions. We are going to do the experiment by dropping three vitamin C tablets with different surface areas into water. We will measure the time taken the reactant to react and fully get dissolved using stop watch with seconds. We are going to stop the stop watch when the bubbles (gas) produced by the reactant are all gone instead of deciding when to stop by looking at the tablet put in the water physically with eyes. We will do this because for the one with the smallest surface area, it will

INVESTIGATING FACTORS WHICH AFFECT THE RATE OF A CHEMICAL

Student’s name: Su Yun (Sue) Jeong

Teacher’s name: Ms. Bellafiore

Homeroom: 8SG

Due Date: Jan, 16

be an easy job but for the one with the biggest surface area which will be the grinded powder one, it will be very hard.

B. Aim: To investigate the effect of changing the surface area of the vitamin C tablet on the reaction between vitamin c tablets and water.

C. Variables:

The variables Changed? Measured? Controlled?Independent variable Surface are of the tablet The first one will be a tablet divided into

half, second one will be 2 of the ¼ of the tablet which will be the same amount and for the last one, and we will grind the half of the tablet into powder. And these are for only 1 trial for each. We are keeping the amount the same only the areas that are facing out to the water.

Dependent variable Rate, time taken for tablet to react

The time taken for the tablets to react will change depending on the surface area, the independent variable. Since they have different area touching water, the time for water to break the tablet into small pieces until we can’t physically see will be different.

Controlled variables

Amount of water The amount of water being used in the experiment will be all same, 150 milliliters. If the amount of water changes, the independent variable will change and there will be 2 independent variables.

Temperature of water The temperature of water will be kept constant since we are changing the surface area. We won’t be able to really control the temperature to keep it same, so we will use the same water source, the tab water so it will at least have similar temperature each time.

The amount of tablet The amount of tablets will be tried to be kept the same. Since we don’t really have equipment that can divide the tablet into 2 exact pieces, we will try our best to cut the tablet.

the size of the beakers The size of the beakers will be kept the same, maximum 300 milliliters beaker. There are many different beakers that can hold different amount of liquid inside. So we want the ones with maximum 300.

INVESTIGATING FACTORS WHICH AFFECT THE RATE OF A CHEMICAL

D. Hypothesis:

If the surface areas of the metals are increased then, the rate of reaction will increase because the more surface contacts between metal and water, the higher the rate of reaction gets.

When the surface area of the reactant increases, it increases the areas that are exposed to the molecules of the other reactant, which will create more collisions. The more collisions they have, faster the reactant reacts. So the reactant with the smallest surface are will be the slowest reactant that will react and fully get dissolved with water. For the smallest surface area one for example, if it has volume of 0.5cm3 which would be about half of the tablet it would react in about 1 minute. And for the grinded powder, the one that the half of the tablet is grinded but still has the same volume of 0.5cm3, would fully react in 20 seconds.

E. Equipment:

Safety glasses 3 vitamin C tablets Paper cutter 6 300ml beakers Mortar and pestle Thermometer Stopwatch Water (900ml)

F. Method:

1. Wear safety glasses to protect your eyes and lab coat2. Gather up all the materials needed for the experiment3. Split up all the tables into half 4. Leave two of the half pieces of tables in a safe place5. Get another two of the half pieces and split them into half pieces again so there should be 4 pieces6. Leave the 4 pieces in a safe place just like the first two half pieces7. Get the other two and grind it up using mortar and pestle carefully one by one and don’t put grinded 2

half pieces together, separate them for 2 trials.8. Measure the weights of all the pieces one by one and 9. Document all the data

10. Fill up 3 beakers with same amount of water. (150ml)11. Name beakers, beaker A, beaker B and beaker C12. Bring one of the half pieces, two of one fourth pieces, and half piece that is grinded13. Set up the timer, get ready to press the starting button14. Hold up the first piece on beaker A and have timer on the other hand15. Drop the piece into beaker A and as soon as you let go the piece, press the starting button to start timing16. Observe beaker A until the piece gets fully dissolved17. Stop the timer as soon as you can no longer see the piece18. Document everything, qualitative data and quantitative data19. Do the same thing with the second one and then third one20. Clean the beakers and fill in the water again for the second trial for each21. Clean up all the mess

G. Diagram of Apparatus

Stop watch

300ml beaker

Water (150ml)

Vit C tablet

(1/2, 2 of ¼ and powdered)

H. Data collection

Quantitative, quantitative data:

Amount of tablets: about 15 grams used for each trial

The temperature of the solvent: 21.5 degrees Celsius

Trial 1 (seconds) Trial 2 (seconds) Average

Half

130 120.13

125.07

2 of 1/4

112 98.72

105.36

grinded

32.39 39.7436.07

For all the trials, every time when we could see what’s going on after the bubbles in the water, the color was changed all the time. And later on, until it got fully dissolved into water, the color was full yellowish orange and spelled a bit like lemon, something like sweet and sour.

And for the trials with grinded tablets, as soon as the powder was dropped into the water, it was fizzing violently and creating lots of bubbles but took some time after to get rid of all the bubbles.

I. Processing and presenting data

Calculations:

Half: (130 + 120.13) / 2 = 125.07

2 quarters: (112 + 98.72) / 2 = 105.36

Grinded: (32.39 + 39.74) / 2 = 36.07

Rate of reaction: (1/time)

Half: 1/125.07 (sec-1)

2 quarters: 1/105.36 (sec-1)

Grinded: 1/36.07 (sec-1)

J. Conclusion

Changing the surface area of the reactant does affect the time that takes the reactants to react. All three of reactants with different surface area had different starting, well the half tablet and 2 of the ¼ started similar but the second one was slightly creating more

Half 2 quarters grinded0

20

40

60

80

100

120

140

125.07

105.36

36.07

Time taken for tablets to react

types of different surface area

Aver

age

time

take

n (s

econ

ds)

Trial 1 (seconds) Trial 2 (seconds) Average0

20

40

60

80

100

120

140 130120.13 125.07

11298.72

105.36

32.3939.74 36.07

Time taken for tablets to react

Half2 quartersgrinded

Types of different surface area

time

take

n fo

r rea

ction

(sec

onds

)

effervescences. And for the third one, which would be the reactant that was grinded into powder form was crazily reacting. And there were huge differences for the results, almost 30 seconds between 2, and 1 minute between the first one and the last one. And also, for the results, I have found something on internet saying someone did the same experiment just like I did with same independent variable, the surface area but with different reactant and that person got the same result as ours, saying the biggest surface area one was the fastest.

The result didn’t really support the hypothesis that I wrote before the experiment. I predicted that the half one would take about 60 seconds to react and 20 seconds for the grinded reactant and the results were, average of 125.07 seconds for the first one and the average of 36.07 seconds. But the opinion that I stated, the one with the smallest surface area will be the slowest one, was correct. And yes, when there are more areas being exposed to the water, there are more collisions which will help the reactant to react faster.

Application

You are given 5 metals CU/Al/Zn/Fe/Mg and you are asked to rank those 5 metals in order from most reactive to least reactive. Use the knowledge that you joined from your tablets activity/report. Only apply your chosen variable on the 5 metals. Present predicted results only and classify the metals.

For the metals, if I am given 5 metals Cu/Al/Zn/Fe/Mg, the rank of how reactive they are would be Mg > Al > Zn > Fe > Cu. Bigger the size of the atom is, less energy required to ionize the energy. Also, if we check out the electronegativity which is the attraction between the shared electrons and the nucleus in the bonding, of each element, lesser it is a metal, more reactive it is. And for the vitamin C experiment, our independent variable was the surface area, and if we choose one of the 5 metals, Cu/Al/Zn/Fe/Mg, Mg, Magnesium, the result will still be the same, the bigger the contact, faster the reaction react. The time that takes won’t be the same since they are different, but other than that, it will be the same.

rank 1st 2nd 3rd 4th 5thTypes of elements

Mg (Magnesium)

Al (Aluminum)

Zn(Zinc)

Fe(Iron)

Cu(Copper)

Also, we have 3 other choices, for the independent variables, and those are, the quantity of the acid, the temperature of the acid and the quantity of reactant. So the first one, quantity of the acid, it has higher saturation level since it has different amount. More acid there is, faster the reactant will react. The second one, the temperature of the acid, according to the KMT, higher the temperature is, more movements molecules have and it will collide more. And the last one, the quantity of reactant, for this one, it is simply the amount of the reactant and less amount of the reactant, takes less time to break them down. Also, there’s one more, the concentration of the acid. Greater the concentration of acid, more the effective molecules collide.

K. Evaluation

The hypothesis was valid, that the prediction that I made for the time taking for reactant to react wasn’t correct, but the statement was correct. So the independent variable, which is the surface area affected the dependent

variable, which is the time taken by having more areas being contacted to the water which can break down the tablet. The method was very valid, that we did the exact same thing as it was on my method and it was very nice. Also, the whole experiment in the lab was quite easy to do. Except there were some parts challenging but it had nothing to do with the method. It wasn’t possible for us to control some stuffs like temperature since we didn’t have the equipment that could help us.

Weaknesses ImprovementsMasses of the tablets. All tablets had different mass, that it was supposed to be controlled but we couldn’t.

We should use sharper knife to cut the tablets instead of big round metal so we can at least have only small differences.

Supplies. We didn’t have enough tablets, 4 tablets were given to each group. So we could only have 2 trials and it should have been at least 3 trials so the average is closer to the real result.

We should buy for ourselves or change the independent variable that does not need too many tablets.

Temperature of the water. We couldn’t control the temperature and also while the reactant was put into the water, the temperature couldn’t be kept the same because of the environment. So we decided to use the same water source which was just the tab water.

It would be very easy if we have the equipment that can control the temperature. The one that uses electricity to heat up the water when it gets cold.

Works sited:

"Factors Affecting Reaction Rates." ThinkQuest. Oracle Foundation, n.d. Web. 15 Jan. 2014.

<http://library.thinkquest.org/C006669/data/Chem/kinetics/factors.html>.

Ozgur, Suzan. "Lab 6-2: Factors Affecting Reaction Rate - Suzan Ozgur's Science Lab."Suzan Ozgur's Science

Lab. N.p., n.d. Web. 15 Jan. 2014. <http://science10suzan.weebly.com/lab-6-2-factors-affecting-reaction-

rate.html>.

Rennie. "Why Will the Surface Area Affect the Rate of Reaction?" WikiAnswers. Answers, n.d. Web. 15 Jan.

2014. <http://wiki.answers.com/Q/Why_will_the_surface_area_affect_the_rate_of_reaction>.

Criterion B: Inquiring and designing

Maximum: 8 Students should be able to:i. describe a problem or question to be tested by a scientific investigation

ii. outline a testable hypothesis and explain it using reasoningiii. describe how to manipulate the variables, and describe how data will be collectediv. design scientific investigations. 

Achievement level

Level descriptor

0 The student does not reach a standard described by any of the descriptors given below.

1 - 2 The student:i. attempts to state a problem or question to be tested by a scientific investigation

ii. is able to state a testable hypothesisiii. is able to state the variablesiv. attempts to design a method.

3 - 4 The student is able to:i. state a problem or question to be tested by a scientific investigation

ii. outline a testable hypothesis using scientific reasoningiii. outline how to manipulate the variables, and state how relevant data will be collectediv. design a safe method in which he or she selects materials and equipment.

5 - 6 The student is able to:i. outline a problem or question to be tested by a scientific investigation

ii. outline and explain a testable hypothesis using scientific reasoningiii. outline how to manipulate the variables, and outline how sufficient, relevant data will be

collectediv. design a complete and safe method in which he or she selects appropriate materials and

equipment.

7 - 8 The student is able to:i. describe a problem or question to be tested by a scientific investigation

ii. outline and explain a testable hypothesis using correct scientific reasoningiii. describe how to manipulate the variables, and describe how sufficient, relevant data will

be collectediv. design a logical, complete and safe method in which he or she selects appropriate

materials or equipment.

 Command termsDescribe Give a detailed account or picture of a situation, event, pattern or process

Design Produce a plan, simulation or model

Explain Give a detailed account including reasons or causes

Outline Give a brief account

State Give a specific name, value or other brief answer without explanation or calculation