Variable
Reaction Instructions:
Use 20cm3
of acid and 10g of marble chips for each experiment (unless the instructions
say otherwise). Pour the acid into the conical flask, add the marble chips
start timing and stop up the flask. After 1 min, read how much the piston moved
out, and record in the tables below.
These are the basic instructions; also follow the instructions below for
each part. Don’t forget to wash the conical flask with water before you do a
new experiment, so that the results for the last experiment don’t affect the
next one!
a) How does the amount of marble chips
(reactant) affect the reaction rate? Weigh out 5g of marble chips for one
experiment and 10g for the second experiment.
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Hypothesis |
Reaction Rate |
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Control Reaction |
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# chips = |
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# chips = |
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b) How does the size of the marble chips
affect the reaction rate? Weigh out 10g of each large and small marble chips
for each experiment.
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Hypothesis |
Reaction Rate |
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Control Reaction |
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Small chips |
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Large chips |
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c) How does temperature affect the reaction
rate? Do one experiment at room temperature, and the second one on a heated hot
plate.
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Hypothesis |
Reaction Rate |
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Control Reaction |
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Temperature |
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Temperature |
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d) Will agitation change the reaction rate? Do
one experiment gently shaking the reaction mixture once or twice, and second
experiment gently swirl the reaction flask frequently (through out the
experiment time).
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Hypothesis |
Reaction Rate |
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Control (no
agitation) |
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Agitation 1: |
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Agitation 2: |
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e) How does watering down the acid change the
rate of reaction? Try adding 10cm3 of water to 10cm3 of
acid and using that for one reaction.
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Hypothesis |
Reaction Rate |
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Control Reaction |
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1M Acid (strong
acid): |
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0.5M (water
added): |
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**
Based on what you have observed, what variables cause the fastest reaction?
Using what you
have learned, design an experiment that will cause chocolate pieces to melt the
fastest.