Using A Burette: Expert Tips For Practical Work 1
Using A Burette: Expert Tips For Practical Work 1
Using A Burette: Expert Tips For Practical Work 1
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20
Accuracy in measuring volumes of liquids 15
Think about the accuracy needed in your measurements. A volumetric pipette 12.4 cm3
10
Measuring cylinders are less accurate. They can usually be read only to the
nearest 1 cm3 or 2 cm3. The larger the measuring cylinder, the less accurate
it is. So you use them only when approximate volumes of liquids are being
measured.
OUP 2015: this may be reproduced for class use solely for the purchasers institute
OUP 2015: this may be reproduced for class use solely for the purchasers institute
time
0 20 40 60 80 100
/s
volume of gas
/ cm3
or this:
time volume of gas
/s / cm3
0
20
40
60
80
100
Dont forget that the number zero for time, volume or other quantity should be included in the table.
When filling in your table of results, check to see if a repeat result is close enough to the others to
be useful, and not an anomalous result.
When filling in your table of results, check to see if the independent variable is changing as you
expect it to.
Make sure that the range of data is enough to draw a sensible graph. For example, if the volumes
of gas in the above example are 3 cm3, 5 cm3, 6 cm3 and 8 cm3, the error in measuring these
volumes would be too great to draw sensible conclusions from the experiment.
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100
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Drawing conclusions
The conclusions drawn from your graphs or tables of data
should be written in the form: the higher the ., the
greater the ., or: the lower the ., the lower the .
Concentration of acid Time
For example, the higher the concentration of hydrochloric
(a) Two curved graphs (b)
acid, the greater the rate of reaction.
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