A level Biology Paper 5 Notes

CO2: Usually, most of the CO2 absorbants are with -OH eg: NaOH or KOH Sources of CO2 are usually those with the -CO3 eg: CaCO3, H2CO3 a non-chemical source: gas cyliner the gas is su!!lie through a bubbler" to measure CO2 concentration: use !robe with meter #em!erature: • • • • •

metho of controlling: use an electronic water-bath $a bea%er of boiling water&- depends on the experiment  use an electronic thermostat heat screen'( heat filter 'for uniform istribution of heat" •

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incubator igital(mercury thermometer for foo tests, such as )eneict*s test, the tem! must be abo+e *C"

#ime:  .lways mention: - the method of timing ( sto!watch( sto!watch( wall cloc%& - precise time -mention the time according to the need  $Teacher's advice: Don't be vague when mentioning the time period; be sensible, realistic and precise! ) Sam!le Si/e: the larger the sam!le si/e, the more reliable the results"  0hen ma%ing concentrations, the minimum number you shoul ma%e is 3" 1eally, the number of conc you*re going to ma%e must be " mass must  be  be the same when com!aring two sam!les" easuring: • •

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use mm cali!ers a ruler- calibrate to cm or mm measuring cyliners syringe, !i!ette  weighing scale( electronic balance igital(mercury thermometer 4.SU51N6 78.N# 84N6#H9" use ruler 2" use a threa threa $remin $remin me to e!lain e!lain what this this means means if i in*t in*t by the the en of of this !ost !ost !lease& O;44N# .N< #14 9" measur measuree ista istance nce mo+e mo+e at at a certa certain in time time $or& $or& • • • • • • •

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2" measure time ta%en for certain istance mo+e  ;O8U4 O= C.7188.5> #U)1N6: 9" mention the iameter 2" an the surface area 5.#4 O= #5.NS715.#1ON?