Physical Science: Speeding Up the Fizz
Introduction:
Chemicals are everywhere. A chemical is a substance that has mass
and takes up space. The simplest substance is an element. You may
have seen a periodic table before. The periodic table lists all
the elements presently known. Some common elements are: |
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An atom is the simplest particle
that describes an element. The center of an atom is called the
nucleus and contains both neutrons and protons. The electrons
orbit around the nucleus. What makes each element unique is the
number of electrons, protons, and neutrons it has. The number
in the lower left-hand corner of the periodic table is the number
of electrons that element has in its most stable form.
A molecule is just a group of bonded atoms that exist as a separate
entity. Can you think of any molecule that is made up of the elements
shown above? Chemists have developed a shorthand notation for
molecules by combining the letter for each element that is contained
in the molecule. If an element is contained twice then a subscript
2 is written next to that element's letter. This shorthand is
called an empirical formula. Can you give the common name for
the following empirical formulas?
H2O: _____________________ CO2: _____________________
O2: ______________________ CH4: _____________________
A chemical reaction is when two molecules come together and undergo
chemical change to form new substances with new properties. Chemical
changes are indicated when any of the following occur: formation
of a gas (bubbles present), formation of a new solid, a color
change, or a gain or loss of heat. In addition, many factors can
affect a chemical reaction - changing how fast the reaction proceeds
or even if the reaction happens. An example is temperature. Some
reactions need to be heated in order for the reaction to occur.
In other cases, some other molecule (called a catalyst) needs
to be present for the reaction to happen. In this lab, you get
the chance to explore the effect of temperature and particle size
has on the rate of a simple chemical reaction. |
Speeding
Up the Fizz:
Teacher Notes
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the "Speeding
Up the Fizz" Teacher's Notes.
Print the "Speeding Up the Fizz" Worksheets.
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Part
A: Effect of Particle Size
To do part A of the lab, get a partner and gather the following
supplies:
- thermometer
- stop watch
- graduated cylinder (100 ml)
- 3 clear plastic cups (7 oz)
- 1 piece of filter paper
- 3 effervescent antacid tablets
- pencil
- water (room temperature)
Procedure:
- Before beginning, have your teacher or parent show you how
to use the stopwatch and print the worksheet.
- Using a graduated cylinder, fill 3 plastic cups each with
100 ml of room temperature water.
- Measure the temperature of the water and record on your worksheet:
Temperature = ____________°C
- Working with a partner: place one full tablet in one of the
glasses of water and time how long it takes for the tablet to
dissolve. One person should place the tablet into the water
and the second should start the stop watch. Stop the stop watch
when you do not see any more of the tablet.
- Record the time the table in the worksheet like the one below.
- Set this cup of water aside.
- Break a second effervescent tablet into 4 pieces.
- Place all 4 pieces into a new glass of water and time how
long it takes for all 4 to dissolve.
- Record the time in the table from the worksheet.
- Set this second cup of water aside
- Take the third effervescent tablet and crumble it into many
pieces. Do this on the filter paper so that you do not loose
any pieces.
- Place all of the crumbled tablet into the third glass and
time how long it takes all the pieces to dissolve.
- Record the time in the table in the worksheet.
- Empty and rinse out all three glasses
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Results:
| Tablet Status: |
Time (seconds) |
| Full tablet (step 5) |
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| Broken Tablet (step 9) |
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| Crumbled tablet (step 16) |
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Discussion:
Which tablet dissolved fastest? Why?
Part
B: Effect of Temperature
To
do part B of the lab, gather these additional supplies:
- 5 effervescent antacid tablets
- hot water
- ice
Procedure:
- Using a graduated cylinder, fill 1 plastic cup with 100
ml of room temperature water.
- Measure the temperature of the water and record in table
below
- Measure how long it takes for one whole tablet (do not crush
or break) to dissolve
- Record the time in the table below
- Set this cup of water aside
- Fill a graduated cylinder with 50 ml of room temperature
water
- Add ice to give a total volume of 100 ml
- Pour the ice/water mixture into a plastic cup and stir.
- Record the temperature when it has reached a constant value.
- Measure how long it takes for one whole tablet (do not crush
or break) to dissolve
- Record the time in the table below
- Set this cup of water aside
- Using a graduated cylinder, fill 1 plastic cup with 100
ml of hot water.
- Measure the temperature of the water and record in table
below
- Measure how long it takes for one whole tablet (do not crush
or break) to dissolve
- Record the time in the table below
- Set this cup of water aside
- Repeat this procedure using different temperatures of water,
record your results in the table in the worksheet.
Results:
| Temperature
(°C) |
Time (seconds) |
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Discussion:
Did the tablet dissolve faster in hot water or cold? Why?
Why was it important to use a whole tablet each time?
Analysis of the results obtained
in Part B:
Plot temperature (x-axis) vs. time (y-axis) on a graph using
your results from part B.
Discussion:
Does your data lie in a straight line?
Draw a smooth curve through your points. Pick a temperature
that lies between temperatures you have already measured. Using
the graph, predict how many seconds it will take the tablet
to dissolve. Try the experiment. Does your prediction agree
with your measurement?
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