Fla
mm
able
subs
, tance: keep the substance away from naked flame
Volatile liquid/gas: Use a fume cupboard and use gloves
To ensure that drying process for a solid is complete, heat to constant mass. This ensures all water
has been evaporated.
Since alcohols are highly flammable, it is dangerous to heat them on a naked flame - use a water
bath to heat alcohols and mixtures containing alcohols
CO2 and O2 are water soluble gases (oxygen is only slightly soluble)
To increase reliability, repeat experiment trial multiple times and take average reading
In electrolysis, some deposited metal could possibly fall off the electrode while washing it, leading to
a lower reading of mass than expected.
While weighing a mass to prepare standard solution, weigh a larger mass to reduce percentage error
and make experiment more accurate.
Always use distilled water in experiments since tap water may contain dissolved ions which alter its
boiling point and may interfere with experimental results
If a heated solution is left without a lid, water may evaporate, changing the concentration of
reactants, heat loss also occurs
In any condenser, cold water always enters at the bottom
To control exothermic reactions, add reactants dropwise.
Certain reaction enthalpies cannot be measured directly since it is impossible to know when the
reaction is complete.
Before starting an experiment where temperature is measured, allow system to equilibrate and reach
the same temperature
In an experiment where temperature is measured, stirring the mixture will make results more
reliable since this ensures uniform heating of solution
Initial trial experiments are done to calibrate instruments
When a hot solid is being made to react with a gas, the gas may be passed over it before the solid is
begun to be heated and after it has finished reacting. This is to prevent the solid from reacting with
other gases in air.
Instruments must be wiped to ensure they are clean and dry to prevent water/dirt does not interfere
with results
When taking volume measurements use lower meniscus for liquids with concave meniscus, and
upper meniscus for liquids with convex meniscus
In a decomposition reaction, if heating is very strong, time measurement will be very small,
increasing the percentage error and reducing accuracy of reaction. At the same time, underheating
may not ensure that all of the solid has decomposed.
To make sure titration is accurate, repeat the experiment and make sure the difference between the
results is 0.1cm3 and concordant
mm
able
subs
, tance: keep the substance away from naked flame
Volatile liquid/gas: Use a fume cupboard and use gloves
To ensure that drying process for a solid is complete, heat to constant mass. This ensures all water
has been evaporated.
Since alcohols are highly flammable, it is dangerous to heat them on a naked flame - use a water
bath to heat alcohols and mixtures containing alcohols
CO2 and O2 are water soluble gases (oxygen is only slightly soluble)
To increase reliability, repeat experiment trial multiple times and take average reading
In electrolysis, some deposited metal could possibly fall off the electrode while washing it, leading to
a lower reading of mass than expected.
While weighing a mass to prepare standard solution, weigh a larger mass to reduce percentage error
and make experiment more accurate.
Always use distilled water in experiments since tap water may contain dissolved ions which alter its
boiling point and may interfere with experimental results
If a heated solution is left without a lid, water may evaporate, changing the concentration of
reactants, heat loss also occurs
In any condenser, cold water always enters at the bottom
To control exothermic reactions, add reactants dropwise.
Certain reaction enthalpies cannot be measured directly since it is impossible to know when the
reaction is complete.
Before starting an experiment where temperature is measured, allow system to equilibrate and reach
the same temperature
In an experiment where temperature is measured, stirring the mixture will make results more
reliable since this ensures uniform heating of solution
Initial trial experiments are done to calibrate instruments
When a hot solid is being made to react with a gas, the gas may be passed over it before the solid is
begun to be heated and after it has finished reacting. This is to prevent the solid from reacting with
other gases in air.
Instruments must be wiped to ensure they are clean and dry to prevent water/dirt does not interfere
with results
When taking volume measurements use lower meniscus for liquids with concave meniscus, and
upper meniscus for liquids with convex meniscus
In a decomposition reaction, if heating is very strong, time measurement will be very small,
increasing the percentage error and reducing accuracy of reaction. At the same time, underheating
may not ensure that all of the solid has decomposed.
To make sure titration is accurate, repeat the experiment and make sure the difference between the
results is 0.1cm3 and concordant
