Science Project!!!

Big Question

How does temperature affect the speed of a chemical reaction???

Hypothesis

All matter is made of tiny molecules. Molecules are groups of atoms that are chemically stuck together. A water molecule is made of two hydrogen atoms stuck to one oxygen atom. I think hot molecules will react faster than cold molecules because they have more energy

References

• http://en.wikipedia.org/wiki/Chemical_kinetics

• http://www.purchon.com/chemistry/rates.htm

• http://books.google.com/books?id=MCyU91APOP0C&pg=PA38&lpg=PA38&dq=speed+of+chemical+reactions+temperature&source=bl&ots=gHai2MrOD5&sig=vKBA-fS_REFtSvjYOajQqvsyRjg&hl=en&ei=4YulSoCcEuWd8Qb_yZztDw&sa=X&oi=book_result&ct=result&resnum=4#v=onepage&q=speed%20of%20chemical%20reactions%20temperature&f=false

• http://books.google.com/books?id=791AAAAAIAAJ&pg=PA81&lpg=PA81&dq=speed+of+chemical+reactions+temperature&source=bl&ots=PfJYcB3h4H&sig=btehNx-2tC8li4czQqvR8HBQqRg&hl=en&ei=4YulSoCcEuWd8Qb_yZztDw&sa=X&oi=book_result&ct=result&resnum=7#

• http://www.sciencebuddies.com/science-fair-projects/project_ideas/Chem_p027.shtml?fave=no&isb=c2lkOjEsaWE6Q2hlbSxwOjEscmlkOjMzMTc1NjE&from=TSW

Experiment

1. Kettle2. Ice water3. Pyrex measuring cup4. Digital thermometer5. Stop watch6. Alka-Seltzer pils

Instructions

1. Pour 200mL of iced water into Pyrex cup2. Measure the temperature of the water with

the digital thermometer and record it.3. Quickly drop Alka-Seltzer pill in the water and

immediately and start the stop watch4. Wait until the pill dissolves and stop the stop

watch and record the time5. Throw away water

Instructions

6. Mix ice water and boiling water from kettle in the Pyrex cup so that the temperature of the mix is about 10 degrees Celsius warmer than before

7. Repeat steps 2-6 until you use only boiling water

8. Plot a graph of the temperature against the time it takes the pill to dissolve

Experiment

IMG_0107.MOV

Analysis of Data

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

160

Speed of Reaction

Temperature / C

Tim

e /

s

Conclusion

My experiment proved my hypothesis. The speed of the chemical reaction increased as the water got hotter. However at about 30 degrees the reaction stopped getting faster. This might be because there were so many bubbles that they kept the water away from the pill so it could not react..

If I would repeat the experiment I would try a different chemical reaction that did not give off gas.

Questions???

Some other questions to explore are: does the reaction speed change with other liquids? How much gas is created by the reaction?

THANKS FOR WATCHING!!!