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Research‌‌Question:‌‌‌How‌‌do‌‌different‌‌antacids‌‌differ‌‌in‌‌their‌‌effectiveness‌‌in‌‌alleviating‌‌medical‌‌conditions‌‌
such‌‌as‌‌heartburn,‌‌acid‌‌reflux‌‌and‌‌indigestion,‌‌measured‌‌by‌‌their‌‌ability‌‌to‌‌neutralise‌‌0.5M‌‌Hydrochloric‌‌acid?‌ ‌
‌
Introduction(Personal‌‌Engagement):‌ ‌
As‌‌a‌‌child,‌‌I‌‌have‌‌always‌‌been‌‌curious‌‌about‌‌the‌‌human‌‌body‌‌and‌‌how‌‌it‌‌works.‌‌In‌‌primary‌‌school,‌‌I‌‌was‌‌taught‌‌
that‌‌the‌‌nutrients‌‌in‌‌the‌‌food‌‌going‌‌through‌‌our‌‌mouths‌‌is‌‌broken‌‌down‌‌in‌‌the‌‌stomach.‌‌However,‌‌I‌‌have‌‌never‌‌
known‌‌how‌‌the‌‌stomach‌‌actually‌‌breaks‌‌down‌‌food.‌‌ ‌
‌
Also,‌‌as‌‌a‌‌sophisticated‌‌foodie‌‌who‌‌enjoys‌‌eating‌‌foods‌‌containing‌‌a‌‌lot‌‌of‌‌spice‌‌and‌‌oil,‌‌I‌‌sometimes‌‌get‌‌painful‌‌
stomach‌‌aches,‌‌which‌‌often‌‌won’t‌‌go‌‌away‌‌for‌‌hours.‌‌Once,‌‌late‌‌at‌‌night‌‌during‌‌Chinese‌‌new‌‌year,‌‌I‌‌got‌‌up‌‌and‌‌
stretched‌‌after‌‌eating‌‌too‌‌much,‌‌and‌‌I‌‌got‌‌a‌‌painful‌‌sensation‌‌in‌‌my‌‌back.‌‌Recently,‌‌I‌‌have‌‌learnt‌‌that‌‌these‌‌
phenomena‌‌are‌‌symptoms‌‌of‌‌indigestion‌‌and‌‌heartburn‌‌respectively,‌‌both‌‌caused‌‌by‌‌an‌‌excess‌‌of‌‌stomach‌‌acids,‌‌
and‌‌antacids‌‌tablets‌‌are‌‌a‌‌possible‌‌treatment‌‌method.‌‌‌(I‌ndigestion‌,‌‌n.d.)‌ ‌

om
‌

l.c
My‌‌curiosity‌‌for‌‌the‌‌human‌‌body,‌‌as‌‌well‌‌as‌‌personal‌‌experience,‌‌is‌‌what‌‌led‌‌me‌‌to‌‌choose‌‌to‌‌investigate‌‌the‌‌

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effectiveness‌‌of‌‌different‌‌antacids.‌‌

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‌

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Introduction(Background‌‌information):‌ ‌
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Stomach‌‌acids‌‌are‌‌acids‌‌in‌‌the‌‌stomach‌‌that‌‌prevents‌‌infection‌‌and‌‌aids‌‌in‌‌digestion‌‌by‌‌breaking‌‌down‌‌complex‌‌
te
nutrients,‌‌such‌‌as‌‌starch,‌‌into‌‌simpler‌‌constituent‌‌molecules,‌‌such‌‌as‌‌glucose,‌‌that‌‌the‌‌body‌‌can‌‌easily‌‌absorb‌‌
iu

and‌‌use‌‌as‌‌energy.‌ ‌Stomach‌‌acids‌‌are‌‌composed‌‌mostly‌‌of‌‌acids‌‌at‌‌a‌‌pH‌‌of‌‌1.5-2,‌‌and‌‌digestive‌‌enzymes.‌‌
ic

(‌Stomach‌‌Acid‌,‌‌n.d.)‌.‌‌Although‌‌they‌‌are‌‌crucial‌‌for‌‌digestion,‌‌an‌‌excess‌‌of‌‌stomach‌‌acids‌‌in‌‌the‌‌stomach‌‌can‌‌cause‌ ‌
ev

painful‌‌stomach‌‌aches,‌‌as‌‌well‌‌as‌‌diseases‌‌like‌‌heartburn,‌‌acid‌‌reflux‌‌and‌‌indigestion.‌ ‌
ul

‌
at

Hydrogen‌‌Chloride‌‌is‌‌a‌‌colourless,‌‌inorganic‌‌gaseous‌‌molecule‌‌that‌‌produces‌‌irritating‌‌and‌‌poisonous‌‌vapour.‌‌
am

(‌Hydrochloric‌‌Acid‌,‌‌2020)‌‌Hydrochloric‌‌acid,‌‌or‌‌HCl(aq),‌‌is‌‌an‌‌acidic,‌‌aqueous‌‌solution‌‌found‌‌in‌‌the‌‌human‌‌
id

stomach,‌‌formed‌‌when‌‌Hydrogen‌‌Chloride‌‌is‌‌dissolved‌‌in‌‌water.‌‌In‌‌modern‌‌times,‌‌it‌‌is‌‌produced‌‌from‌‌the‌‌
va

double‌‌displacement‌‌reaction‌‌of‌‌Salt‌‌and‌‌Sulfuric‌‌acid:‌ ‌
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2NaCl‌(s)‌+‌
‌ ‌H‌2‌SO‌4(aq)‌→‌‌2HCl‌(aq)‌+‌
‌ ‌Na‌2‌SO‌4(s)‌ ‌ ‌
tif

‌
‌(Speight,‌‌2017,‌‌p.‌‌[Page‌‌#])‌ ‌
as

Electronegativity‌‌is‌‌defined‌‌as‌‌“the‌‌measure‌‌of‌‌the‌‌tendency‌‌of‌‌an‌‌atom‌‌to‌‌attract‌‌a‌‌bonding‌‌pair‌‌of‌‌
Cl

electrons”‌(Clark,‌‌2000)‌.‌‌As‌‌hydrogen‌‌and‌‌chlorine‌‌have‌‌a‌‌very‌‌high‌‌electronegativity‌‌difference,‌‌chlorine‌‌attracts‌‌
the‌‌bonding‌‌pair‌‌of‌‌electrons‌‌stronger‌‌than‌‌hydrogen,‌‌inducing‌‌a‌‌dipole‌‌moment.‌‌This‌‌dipole‌‌moment‌‌makes‌‌
HCl(aq)‌‌a‌‌strong‌‌acid‌‌as‌‌it‌‌is‌‌very‌‌willing‌‌to‌‌give‌‌up‌‌its‌‌Hydrogen‌‌atom.‌‌A‌‌strong‌‌acid‌‌means‌‌HCl(aq)‌‌is‌‌able‌‌to‌‌
fully‌‌dissociate‌‌in‌‌water,‌‌becoming‌‌a‌‌cation(H+)‌‌and‌‌anion(Cl-)‌‌through‌‌the‌‌following‌‌chemical‌‌equations.‌ ‌
HCl‌(aq)‌+H‌2‌O‌(l)‌‌ ‌→‌‌H3‌‌ O‌+‌(aq)‌+Cl‌-‌(aq)‌‌ ‌AND‌ ‌
HCl‌(aq)‌→H‌+‌(aq)‌+Cl‌-‌(aq)‌ ‌ ‌
(Helmenstien,‌‌2019)‌ ‌
A‌‌neutralization‌‌reaction‌‌is‌‌when‌‌aqueous‌‌solutions‌‌of‌‌acids‌‌and‌‌bases‌‌react‌‌with‌‌each‌‌other‌‌to‌‌form‌‌water(using‌‌
H+‌‌and‌‌OH-‌‌ions)‌‌and‌‌salt.‌‌Strong‌‌acids‌‌and‌‌bases‌‌neutralize‌‌to‌‌a‌‌pH‌‌of‌‌7,‌‌whilst‌‌strong‌‌acids‌‌and‌‌weak‌‌bases,‌‌
strong‌‌bases‌‌and‌‌weak‌‌acids‌‌neutralize‌‌to‌‌a‌‌pH‌‌below‌‌7‌‌and‌‌above‌‌7‌‌respectively.‌(‌Dunn‌‌&‌‌Chappell,‌‌2020)‌ ‌
‌
Antacids‌‌are‌‌medical‌‌tablets‌‌that‌‌contain‌‌active‌‌ingredients(bases)‌‌which‌‌aim‌‌to‌‌neutralise‌‌excess‌‌HCl(aq)‌‌acid‌‌
in‌‌the‌‌stomach‌‌to‌‌alleviate‌‌symptoms‌‌of‌‌heartburn,‌‌acid‌‌reflux‌‌and‌‌indigestion.‌‌The‌‌antacids‌‌that‌‌we‌‌will‌‌be‌‌
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1‌ ‌
working‌‌on‌‌in‌‌this‌‌experiment‌‌are‌‌Actal,‌‌which‌‌has‌‌only‌‌Aluminium‌‌Hydroxide‌‌as‌‌the‌‌active‌‌ingredient,‌‌and‌‌
Magsil,‌‌Maalox‌‌Plus,‌‌and‌‌Hydrosil,‌‌which‌‌have‌‌both‌‌Aluminium‌‌Hydroxide‌‌and‌‌Magnesium‌‌Hydroxide‌‌as‌‌the‌‌
active‌‌ingredients.‌(‌F‌ ind‌‌Drugs‌,‌‌n.d.)‌ ‌
‌
Compound‌‌name‌ ‌ Formula‌ ‌ Balanced‌‌equation‌‌of‌‌reaction‌‌with‌‌HCl(aq)‌ ‌

Aluminium‌‌Hydroxide‌ ‌ Al(OH)‌3‌ ‌ Al(OH)‌3(s)‌+‌‌3HCl‌(aq)‌‌ ‌->‌‌3H‌2‌O‌(l)‌‌ ‌+‌‌AlCl‌3(aq)‌ ‌

Magnesium‌‌Hydroxide‌ ‌ Mg(OH)‌2‌ ‌ Mg(OH)‌2(s)‌+‌‌2HCl‌(aq)‌‌ ‌->‌‌2H‌2‌O‌(l)‌‌ ‌+‌‌AlCl‌3(aq)‌ ‌

‌‌
Titration‌‌is‌‌a‌‌method‌‌of‌‌determining‌‌the‌‌concentration‌‌of‌‌a‌‌known‌‌analyte‌‌by‌‌reacting‌‌it‌‌with‌‌another‌‌solution‌‌of‌‌
known‌‌concentration.‌‌Back‌‌titration‌‌is‌‌similar‌‌to‌‌titration‌‌whereby‌‌the‌‌analyte‌‌is‌‌reacted‌‌with‌‌a‌‌known‌‌
concentration‌‌of‌‌excess‌‌reagent,‌‌and‌‌the‌‌excess‌‌is‌‌then‌‌titrated‌‌normally.‌‌(T ‌ itration‌,‌‌2019)‌‌ ‌

om
‌

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As‌‌both‌‌compounds‌‌are‌‌metal‌‌hydroxides,‌‌both‌‌can‌‌be‌‌considered‌‌as‌‌strong‌‌bases.‌(‌S‌ trength‌‌of‌‌Bases‌,‌‌n.d.)‌‌

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However,‌‌both‌‌compounds‌‌have‌‌limited‌‌solubility,‌‌thereby‌‌are‌‌weak‌‌alkalis.‌‌According‌‌to‌‌the‌‌lab‌‌guide‌‌

gm
provided,‌‌the‌‌tablets‌‌also‌‌contain‌‌other‌‌elements,‌‌including‌‌binders,‌‌fillers‌‌and‌‌flavours,‌‌which‌‌may‌‌interfere‌‌
with‌‌the‌‌reaction‌‌and‌‌slow‌‌it‌‌down.‌‌These‌‌two‌‌points‌‌hinder‌‌the‌‌accuracy‌‌of‌‌the‌‌end‌‌point‌‌of‌‌direct‌‌titration‌‌with‌‌

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HCl(aq),‌‌which‌‌is‌‌why‌‌back‌‌titration‌‌is‌‌used.‌ ‌
‌
93
te
The‌‌first‌‌step‌‌of‌‌the‌‌back-titration‌‌involves‌‌the‌‌reaction‌‌of‌‌the‌‌active‌‌ingredients‌‌of‌‌the‌‌antacid‌‌tablets‌‌with‌‌
iu
ic

excess‌‌HCl(aq)‌‌at‌‌known‌‌concentrations‌‌and‌‌volume.‌‌The‌‌second‌‌step‌‌involves‌‌using‌‌the‌‌titrant‌‌Sodium‌‌
ev

Hydroxide,‌‌or‌‌NaOH(aq),‌‌to‌‌titrate‌‌the‌‌excess‌‌of‌‌the‌‌HCl(aq):‌ ‌
ul

HCl(aq)+NaOH(aq)‌‌→‌‌NaCl(aq)‌‌+‌‌H2‌‌ O(l)(Reaction‌‌equation)‌ ‌
at

H‌+‌(aq)+OH‌-‌(aq)→H‌2‌O(l)(Ionic‌‌equation‌‌without‌‌spectator‌‌ions)‌ ‌
am

‌
The‌‌effectiveness‌‌of‌‌the‌‌antacid‌‌tablets‌‌will‌‌be‌‌determined‌‌by‌‌the‌‌moles‌‌of‌‌HCl(aq)‌‌which‌‌was‌‌neutralized‌‌by‌‌
id

the‌‌tablet.‌‌Factors‌‌that‌‌can‌‌affect‌‌the‌‌effectiveness‌‌of‌‌the‌‌antacid‌‌include‌‌the‌‌mass‌‌of‌‌the‌‌antacid‌‌tablet,‌‌the‌‌
va

percentage‌‌composition‌‌of‌‌the‌‌active‌‌ingredient‌‌in‌‌the‌‌tablet,‌‌and‌‌the‌‌number‌‌of‌‌moles‌‌of‌‌the‌‌active‌
y

ingredient(the‌‌base)‌‌in‌‌the‌‌antacid‌‌tablet.‌ ‌
tif

Hypothesis:‌ ‌
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I‌‌hypothesize‌‌that‌‌the‌‌tablet‌‌that‌‌has‌‌the‌‌active‌‌ingredient‌‌with‌‌the‌‌highest‌‌stoichiometric‌‌ratio‌‌will‌‌be‌‌the‌‌most‌‌
Cl

effective‌‌in‌‌neutralizing‌‌HCl(aq).‌‌This‌‌would‌‌mean‌‌that‌‌Actal‌‌will‌‌be‌‌the‌‌most‌‌effective,‌‌and‌‌the‌‌tablets‌‌Magsil,‌‌
Maalox‌‌Plus‌‌and‌‌Hydrosil‌‌will‌‌have‌‌similar‌‌effectiveness.‌‌As:‌ ‌
n(Al(OH)‌3‌)‌‌:‌‌n(‌HCl)‌‌=‌‌1:3‌ ‌
n(Mg(OH)‌2‌)‌‌:‌‌n(‌HCl)‌‌=‌‌1:2‌ ‌
We‌‌know‌‌that‌‌assuming‌‌that‌‌the‌‌mass‌‌of‌‌the‌‌tablet,‌‌the‌‌percentage‌‌composition‌‌and‌‌the‌‌number‌‌of‌‌moles‌‌of‌‌the‌‌
active‌‌ingredient‌‌in‌‌the‌‌tablet‌‌remains‌‌constant,‌‌more‌‌HCl(aq)‌‌will‌‌be‌‌neutralized‌‌if‌‌the‌‌active‌‌ingredient‌‌were‌‌
Al(OH)‌3‌‌ ‌rather‌‌than‌‌Mg(OH)‌2‌.‌‌Actal‌‌is‌‌the‌‌only‌‌tablet‌‌that‌‌has‌‌just‌‌Aluminium‌‌Hydroxide‌‌as‌‌the‌‌active‌‌
ingredient,‌‌therefore‌‌it‌‌should‌‌be‌‌most‌‌effective.‌‌ ‌
Variables:‌ ‌
Independent‌‌variable:‌T ‌ he‌‌different‌‌types‌‌of‌‌antacid‌‌tablets‌‌that‌‌will‌‌be‌‌used‌‌for‌‌this‌‌experiment(Magsil,‌‌
Actal,‌‌Hydrosil,‌‌Maalox).‌‌I‌‌will‌‌do‌‌the‌‌experiment‌‌with‌‌4‌‌tablets‌‌of‌‌each‌‌type,‌‌amounting‌‌to‌‌16‌‌trials‌‌in‌‌total.‌ ‌ ‌
Dependent‌‌variable:‌T ‌ he‌‌effectiveness‌‌of‌‌the‌‌antacid‌‌tablet.‌‌This‌‌will‌‌be‌‌derived‌‌from‌‌the‌‌amount‌‌of‌‌moles‌‌of‌‌
HCl(aq)‌‌that‌‌neutralises‌‌with‌‌the‌‌active‌‌ingredient‌‌of‌‌the‌‌tablet.‌ ‌ ‌
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2‌ ‌
How‌‌to‌‌measure:‌T ‌ o‌‌measure‌‌the‌‌amount‌‌of‌‌moles‌‌of‌‌HCl(aq)‌‌reacted,‌‌a‌‌back‌‌titration‌‌procedure‌‌will‌‌be‌‌used,‌‌
as‌‌a‌‌standard‌‌titration‌‌process‌‌will‌‌be‌‌too‌‌slow‌‌and‌‌have‌‌inconsistent‌‌end-points(methodology‌‌described‌‌in‌‌
intro).‌‌An‌‌excess‌‌HCl(aq)‌‌solution‌‌of‌‌a‌‌given‌‌volume‌‌and‌‌concentration‌‌will‌‌be‌‌prepared‌‌and‌‌reacted‌‌with‌‌the‌‌
tablet‌‌in‌‌a‌‌beaker.‌‌The‌‌tablet‌‌will‌‌be‌‌grinded‌‌down‌‌and‌‌put‌‌into‌‌the‌‌beaker,‌‌and‌‌the‌‌mixture‌‌will‌‌be‌‌stirred‌‌to‌‌
ensure‌‌reaction‌‌goes‌‌to‌‌completion.‌‌The‌‌mixture‌‌will‌‌then‌‌be‌‌titrated‌‌with‌‌the‌‌same‌‌concentration‌‌of‌‌NaOH(aq)‌‌
in‌‌order‌‌to‌‌yield‌‌the‌‌moles‌‌of‌‌the‌‌excess‌‌HCl(aq).‌‌By‌‌subtracting‌‌the‌‌moles‌‌of‌‌HCl(aq)‌‌in‌‌the‌‌original‌‌solution‌‌
with‌‌the‌‌moles‌‌of‌‌excess‌‌HCl(aq),‌‌the‌‌moles‌‌of‌‌HCl(aq)‌‌that‌‌reacted‌‌with‌‌the‌‌tablet‌‌can‌‌be‌‌calculated.‌‌ ‌
Controlled‌‌variables:‌ ‌
1. The‌‌volume‌‌of‌‌HCl(aq)‌‌used‌‌to‌‌react‌‌with‌‌the‌‌active‌‌ingredient‌‌in‌‌the‌‌tablet(50ml‌‌per‌‌trial)‌ ‌
2. The‌‌concentration‌‌of‌‌HCl(aq)‌‌used‌‌with‌‌the‌‌tablet(0.5moldm‌-3‌)‌ ‌
3. The‌‌number‌‌of‌‌drops‌‌of‌‌Phenolphthalein‌‌indicator(3‌‌drops)‌ ‌
4. The‌‌concentration‌‌of‌‌NaOH(aq)‌‌used‌‌in‌‌the‌‌titration‌‌of‌‌the‌‌excess‌‌HCl(aq)(0.5moldm‌-3‌)‌ ‌
5. The‌‌masses‌‌of‌‌each‌‌antacid‌‌tablet‌‌that‌‌will‌‌react‌‌with‌‌the‌‌HCl(aq)‌‌solution‌ ‌

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Why‌‌the‌‌variables‌‌need‌‌to‌‌be‌‌controlled:‌ ‌

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1. Although‌‌the‌‌HCl(aq)‌‌solutions‌‌is‌‌an‌‌excess‌‌reactant‌‌in‌‌the‌‌first‌‌reaction,‌‌it‌‌is‌‌the‌‌limiting‌‌reactant‌‌in‌‌the‌‌

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titration‌‌reaction‌‌with‌‌NaOH(aq).‌‌More‌‌HCl(aq)‌‌will‌‌mean‌‌that‌‌there‌‌is‌‌more‌‌HCl(aq)‌‌solution‌‌in‌‌excess,‌‌

gm
thereby‌‌using‌‌up‌‌more‌‌NaOH(aq).‌‌This‌‌will‌‌certainly‌‌affect‌‌the‌‌back-titrations‌‌calculation‌‌and‌‌cause‌‌the‌‌data‌‌to‌‌

@
be‌‌inaccurate.‌‌ ‌
2. 93
The‌‌concentration‌‌of‌‌HCl(aq)‌‌used‌‌with‌‌the‌‌tablet‌‌can‌‌influence‌‌the‌‌number‌‌of‌‌moles‌‌of‌‌HCl(aq)‌‌in‌‌a‌‌
te
controlled‌‌volume.‌‌Similar‌‌to‌‌above,‌‌the‌‌higher‌‌the‌‌concentration‌‌of‌‌HCl(aq),‌‌the‌‌more‌‌HCl(aq)‌‌in‌‌excess,‌‌and‌‌
iu

the‌‌more‌‌NaOH(aq)‌‌will‌‌be‌‌used‌‌up,‌‌which‌‌would‌‌cause‌‌inaccuracies.‌ ‌
ic

3. Since‌‌indicators‌‌work‌‌by‌‌reacting‌‌with‌‌H+‌‌and‌‌OH-‌‌ions‌‌to‌‌induce‌‌colour‌‌change,‌‌more‌‌indicator‌‌will‌‌
ev

mean‌‌more‌‌substance‌‌to‌‌react‌‌with‌‌the‌‌ions,‌‌therefore‌‌a‌‌more‌‌rapid‌‌and‌‌abrupt‌‌colour‌‌change‌‌will‌‌be‌‌detected.‌‌
ul

Since‌‌we‌‌are‌‌using‌‌color‌‌change‌‌as‌‌a‌‌means‌‌of‌‌determining‌‌the‌‌end‌‌point‌‌of‌‌titration,‌‌this‌‌variable‌‌must‌‌be‌‌
at

controlled.‌ ‌ ‌
am

4. The‌‌concentration‌‌of‌‌NaOH(aq)‌‌can‌‌affect‌‌the‌‌endpoint‌‌of‌‌its‌‌titration‌‌with‌‌the‌‌excess‌‌of‌‌the‌‌HCl(aq)‌‌
id

solution,‌‌which‌‌would‌‌negatively‌‌influence‌‌the‌‌accuracy‌‌of‌‌the‌‌back-titration‌‌calculations.‌‌ ‌
va

5. Assuming‌‌that‌‌the‌‌percentage‌‌composition‌‌of‌‌each‌‌antacid‌‌tablet‌‌is‌‌somewhat‌‌consistent‌‌for‌‌each‌‌brand,‌‌
y

changing‌‌the‌‌masses‌‌of‌‌the‌‌antacid‌‌tablets‌‌will‌‌change‌‌the‌‌mass‌‌of‌‌active‌‌ingredients‌‌that‌‌are‌‌in‌‌the‌‌tablet,‌‌which‌‌
tif

would‌‌either‌‌react‌‌with‌‌too‌‌much‌‌or‌‌too‌‌little‌‌HCl(aq),‌‌thereby‌‌decreasing‌‌the‌‌experimental‌‌accuracy.‌‌ ‌
as

How‌‌will‌‌the‌‌variable‌‌be‌‌controlled?‌ ‌
Cl

1. The‌‌volume‌‌of‌‌HCl(aq)‌‌will‌‌be‌‌measured‌‌out‌‌with‌‌a‌‌measuring‌‌cylinder(‌±1ml)‌‌to‌‌a‌‌volume‌‌of‌‌50ml‌‌for‌‌
all‌‌test‌‌cases‌‌and‌‌trials.‌T‌ his‌‌volume‌‌would‌‌guarantee‌‌the‌‌HCl(aq)‌‌is‌‌in‌‌excess‌‌and‌‌would‌‌make‌‌it‌‌easier‌‌for‌‌the‌‌
active‌‌ingredient‌‌to‌‌react‌‌with‌‌HCl(aq).‌‌ ‌
2. I‌‌have‌‌chosen‌‌to‌‌use‌‌0.5moldm‌-3‌‌ ‌since‌‌that‌‌concentration‌‌will‌‌ensure‌‌safety‌‌and‌‌is‌‌the‌‌only‌‌concentration‌‌
provided‌‌by‌‌the‌‌science‌‌department.‌ ‌
3. I‌‌will‌‌use‌‌3‌‌drops‌‌of‌‌Phenolphthalein‌‌for‌‌each‌‌trial.‌‌The‌‌choice‌‌of‌‌3‌‌drops‌‌would‌‌be‌‌ideal‌‌since‌‌that‌‌
would‌‌be‌‌enough‌‌to‌‌show‌‌a‌‌clear‌‌and‌‌unmistakable‌‌change‌‌without‌‌wasting‌‌indicator.‌‌ ‌
4. 0.5moldm‌-3‌‌ ‌is‌‌ideal‌‌for‌‌experimental‌‌purposes‌‌as‌‌it‌‌is‌‌safe‌‌to‌‌handle.‌‌As‌‌NaOH(aq)‌‌is‌‌a‌‌strong‌‌base‌‌and‌‌
reacts‌‌with‌‌HCl(aq)‌‌in‌‌a‌‌1‌‌to‌‌1‌‌ratio,‌‌we‌‌know‌‌that‌‌having‌‌the‌‌concentration‌‌of‌‌NaOH(aq)‌‌the‌‌same‌‌as‌‌HCl(aq)‌‌
would‌‌simplify‌‌back‌‌titration‌‌calculations,‌‌as‌‌volume‌‌of‌‌excess‌‌HCl(aq)‌‌would‌‌be‌‌the‌‌same‌‌as‌‌the‌‌volume‌‌of‌‌
NaOH(aq)‌‌consumed‌‌through‌‌titre.‌ ‌ ‌
5. One‌‌and‌‌only‌‌one‌‌tablet‌‌of‌‌each‌‌antacid‌‌will‌‌be‌‌crushed‌‌down‌‌with‌‌the‌‌mortar‌‌and‌‌pestle‌‌and‌‌reacted‌‌
with‌‌the‌‌HCl(aq)‌‌every‌‌trial.‌‌Given‌‌that‌‌these‌‌tablets‌‌are‌‌mass‌‌produced,‌‌the‌‌company‌‌will‌‌have‌‌specifications‌‌
 Downloaded from www.clastify.com by Vaida Matulevičiūtė

3‌ ‌
which‌‌would‌‌control‌‌the‌‌masses‌‌of‌‌each‌‌tablet.‌‌Using‌‌an‌‌electronic‌‌scale,‌‌we‌‌measured‌‌the‌‌masses‌‌of‌‌each‌‌tablet‌‌
to‌‌be‌‌1.3g,‌‌1g,‌‌0.6g‌‌and‌‌0.7g‌‌for‌‌the‌‌tablets‌‌Maalox‌‌Plus,‌‌Magsil,‌‌Actal‌‌and‌‌Hydrosil‌‌respectively.‌ ‌
Materials(Apparatus):‌ ‌
Equipments‌ ‌ Chemicals‌ ‌

1x‌‌Burette(‌±0‌ .05ml)‌ ‌ 4x‌‌Maalox‌‌Plus‌‌tablets(for‌‌4‌‌trials)‌ ‌

1x‌‌Mortar‌‌and‌‌Pestle‌ 4x‌‌Hydrosil‌‌tablets(for‌‌4‌‌trials)‌ ‌
1x‌‌Retort‌‌Stand‌ ‌ 4x‌‌Actal‌‌tablets(for‌‌4‌‌trials)‌ ‌
1x‌‌Burette‌‌Clamp‌ 4x‌‌Magsil‌‌tablets(for‌‌4‌‌trials)‌ ‌
1x‌‌Bosshead‌ ‌ 800mL‌‌of‌‌0.5moldm‌-3‌HCl‌ ‌
‌solution(4‌‌trials‌‌each‌‌for‌‌4‌‌tablets,‌‌16‌‌
1x‌‌250mL‌‌conical‌‌flask‌ ‌ trials,‌‌50mL‌‌each‌‌trial)‌‌ ‌
1x‌‌Electric‌‌balance(‌±0‌ .1g)‌ ‌ 800mL‌‌of‌‌0.5moldm‌-3‌NaOH‌‌
‌solution(50mL‌‌prepared‌‌for‌‌titration‌‌
1x‌‌funnel‌ ‌ each‌‌trial)‌ ‌
1x‌‌100cm^3‌‌Beaker‌ ‌ Phenolphthalein‌‌indicator‌ ‌

om
1x‌‌Spatula‌ ‌

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1x‌‌50cm3‌‌Measuring‌‌Cylinder(‌±1‌ mL)‌ ‌
1x‌‌Glass‌‌Stirring‌‌rod‌ ‌

ai
1x‌‌Tray‌‌Cup(for‌‌measuring‌‌tablet‌‌weight)‌ ‌

gm
Method:‌ ‌

@
1. Set‌‌up‌‌the‌‌apparatus‌‌as‌‌shown‌‌in‌‌the‌‌diagram‌‌below‌ ‌
2.
93
Put‌‌the‌‌funnel‌‌on‌‌top‌‌of‌‌the‌‌measuring‌‌cylinder(‌±1‌ mL)‌‌to‌‌measure‌‌out‌‌50mL‌‌of‌‌HCl(aq)‌‌solution‌‌at‌‌a‌‌
te
0.5moldm‌-3‌‌ ‌concentration.‌‌ ‌
iu

3. Take‌‌out‌‌a‌‌tablet‌‌of‌‌Hydrosil.‌‌Put‌‌a‌‌tray‌‌cup‌‌on‌‌the‌‌weighing‌‌scale,‌‌zero‌‌the‌‌scale,‌‌and‌‌then‌‌put‌‌the‌‌tablet‌
ic
ev

into‌‌the‌‌cup‌‌to‌‌read‌‌the‌‌weight.‌‌Record‌‌weight‌‌on‌‌a‌‌data‌‌table‌ ‌
ul

4. Grind‌‌the‌‌tablet‌‌using‌‌mortar‌‌and‌‌pestle‌‌to‌‌fine‌‌powder‌ ‌
at

5. Pour‌‌the‌‌HCl(aq)‌‌in‌‌the‌‌measuring‌‌cylinder‌‌and‌‌the‌‌grinded‌‌tablet‌‌into‌‌the‌‌beaker,‌‌and‌‌stir‌‌the‌‌mixture‌‌
am

with‌‌a‌‌glass‌‌rod‌‌for‌‌30‌‌seconds,‌‌to‌‌ensure‌‌that‌‌the‌‌reaction‌‌has‌‌fully‌‌completed.‌‌ ‌
6. Fill‌‌burette‌‌with‌‌50mL‌‌of‌‌NaOH(aq)‌‌solution,‌‌and‌‌record‌‌initial‌‌reading‌‌into‌‌the‌‌data‌‌table‌ ‌
id
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7. Pour‌‌the‌‌mixture‌‌containing‌‌HCl(aq)‌‌into‌‌a‌‌conical‌‌flask,‌‌drop‌‌3‌‌drops‌‌of‌‌indicator,‌‌and‌‌begin‌‌the‌‌
titration‌‌by‌‌opening‌‌the‌‌burette‌‌with‌‌the‌‌handle‌‌at‌‌the‌‌bottom.‌‌Continue‌‌stirring/whirling‌‌the‌‌conical‌‌flask,‌‌and‌‌
y
tif

stop‌‌the‌‌titration‌‌when‌‌solution‌‌contains‌‌a‌‌shade‌‌of‌‌pink,‌‌which‌‌marks‌‌the‌‌end‌‌point.‌‌ ‌
as

8. Record‌‌the‌‌final‌‌reading‌‌of‌‌burette‌‌into‌‌the‌‌data‌‌table‌ ‌
Cl

9. Repeat‌‌the‌‌above‌‌steps‌‌3‌‌times‌‌with‌‌the‌‌same‌‌type‌‌of‌‌antacid‌‌tablet(Hydrosil)‌ ‌
10. Repeat‌‌all‌‌of‌‌the‌‌steps‌‌above‌‌for‌‌the‌‌other‌‌three‌‌antacids(Maalox‌‌Plus,‌‌Actal,‌‌Magsil)‌ ‌
Risk‌‌Assessment:‌ ‌
All‌‌general‌‌lab‌‌safety‌‌rules‌‌will‌‌be‌‌followed.‌‌Safety‌‌goggles‌‌will‌‌be‌‌worn‌‌at‌‌all‌‌times.‌ ‌
Safety‌‌Precautions‌ ‌ Hydrochloric‌‌acid‌‌and‌‌Sodium‌‌Hydroxide‌‌are‌‌corrosive,‌‌strong‌‌acids‌‌and‌‌bases,‌‌and‌‌they‌‌
can‌‌cause‌‌irritation‌‌to‌‌the‌‌skin‌‌and‌‌eyes.‌‌Handle‌‌with‌‌care‌‌and‌‌be‌‌careful‌‌not‌‌to‌‌spill.‌‌
When‌‌in‌‌contact‌‌with‌‌skin,‌‌be‌‌sure‌‌to‌‌rinse‌‌immediately.‌ ‌ ‌

Environmental‌‌Considerations‌ ‌ All‌‌solutions‌‌should‌‌be‌‌disposed‌‌of‌‌through‌‌a‌‌special‌‌container‌‌for‌‌inorganic‌‌waste,‌‌as‌‌
strong‌‌acids‌‌can‌‌corrode‌‌drainage‌‌pipes‌‌and‌‌release‌‌toxic‌‌gas.‌(H
‌ ow‌‌to‌‌Dispose‌,‌‌2018)‌‌ ‌

Ethical‌‌Considerations‌ ‌ Do‌‌not‌‌use‌‌too‌‌much‌‌HCl(aq)‌‌for‌‌each‌‌trial‌‌since‌‌there‌‌may‌‌be‌‌a‌‌limited‌‌amount‌‌prepared‌‌
for‌‌each‌‌science‌‌classroom.‌ ‌
‌
 Downloaded from www.clastify.com by Vaida Matulevičiūtė

4‌ ‌
Diagram/Photograph‌‌of‌‌set-up;‌ ‌
Experimental‌‌setup‌‌for‌‌reaction‌‌1(HCl(aq)‌‌with‌‌the‌‌antacid‌‌tablet):‌ ‌

om
Experimental‌‌setup‌‌for‌‌reaction‌‌2(Titration‌‌of‌‌excess‌‌HCl(aq)):‌ ‌

l.c
ai
gm
@
93
te
iu
ic
ev
ul
at
am
id
va
y
tif
as

‌
Cl

Qualitative‌‌Observations‌ ‌
Before‌‌Titration‌‌with‌‌NaOH(aq)‌ ‌ During‌‌Titration‌‌with‌‌NaOH(aq)‌ ‌ After‌‌Titration‌‌with‌‌NaOH(aq)‌ ‌

A‌‌very‌‌cloudy‌‌and‌‌milky‌‌white‌‌ The‌‌mixture‌‌continue‌‌to‌‌be‌‌cloudy,‌‌and‌‌it‌‌is‌‌ After‌‌the‌‌titration‌‌reached‌‌the‌‌

mixture‌‌was‌‌observed‌‌after‌‌the‌‌ possible‌‌to‌‌observe‌‌very‌‌small‌‌hues‌‌of‌‌pink‌‌ endpoint,‌‌mixture‌‌is‌‌mostly‌‌pink,‌‌
HCl(aq)‌‌was‌‌stirred‌‌with‌‌the‌‌antacid‌‌ as‌‌NaOH(aq)‌‌is‌‌gradually‌‌poured‌‌into‌‌the‌‌ and‌‌is‌‌not‌‌as‌‌cloudy‌‌as‌‌before‌‌the‌‌
tablet.‌‌The‌‌mixture‌‌is‌‌colourless.‌ ‌ conical‌‌flask.‌‌ ‌ titration.‌‌ ‌
Raw‌‌Data:‌ ‌
Table‌‌1.1:‌‌This‌‌table‌‌shows‌‌the‌‌titrant(NaOH)‌‌used‌‌each‌‌trial‌‌for‌‌the‌‌Maalox‌‌Plus‌‌tablet‌‌ ‌
Trial‌ ‌ Initial‌‌Reading‌‌(‌±0‌ .05ml)‌ ‌ Final‌‌Reading(‌±0‌ .05ml)‌ ‌ Difference(‌±0‌ .10ml)‌ ‌

1‌ ‌ 50‌ ‌ 26.5‌ ‌ 23.5‌ ‌

2‌ ‌ 50‌ ‌ 28.2‌ ‌ 21.8‌ ‌

 Downloaded from www.clastify.com by Vaida Matulevičiūtė

5‌ ‌
3‌ ‌ 50‌ ‌ 17.6‌ ‌ 32.4‌ ‌

4‌ ‌ 50‌ ‌ 25.3‌ ‌ 24.7‌ ‌

Table‌‌1.2:‌‌This‌‌table‌‌shows‌‌the‌‌titrant(NaOH)‌‌used‌‌each‌‌trial‌‌for‌‌the‌‌Magsil‌‌tablet‌ ‌
Trial‌ ‌ Initial‌‌Reading‌‌(‌±0‌ .05ml)‌ ‌ Final‌‌Reading(‌±0‌ .05ml)‌ ‌ Difference(‌±0‌ .10ml)‌ ‌

1‌ ‌ 50‌ ‌ 28.4‌ ‌ 21.6‌ ‌

2‌ ‌ 50‌ ‌ 23.8‌ ‌ 26.2‌ ‌

3‌ ‌ 50‌ ‌ 20.5‌ ‌ 29.5‌ ‌

4‌ ‌ 50‌ ‌ 26.3‌ ‌ 23.7‌ ‌
Table‌‌1.3:‌‌This‌‌table‌‌shows‌‌the‌‌titrant(NaOH)‌‌used‌‌each‌‌trial‌‌for‌‌the‌‌Actal‌‌tablet‌ ‌

om
Trial‌ ‌ Initial‌‌Reading‌‌(±
‌ ‌0.05ml)‌ ‌ Final‌‌Reading(‌±0‌ .05ml)‌ ‌ Difference(‌±0‌ .10ml)‌ ‌

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ai
1‌ ‌ 50‌ ‌ 33.5‌ ‌ 16.5‌ ‌

gm
2‌ ‌ 50‌ ‌ 23.5‌ ‌ 26.5‌ ‌

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3‌ ‌ 50‌ ‌ 15.3‌ ‌ 93 34.7‌ ‌
te
4‌ ‌ 50‌ ‌ 30.8‌ ‌ 19.2‌ ‌
iu
ic

Table‌‌1.4:‌‌This‌‌table‌‌shows‌‌the‌‌titrant(NaOH)‌‌used‌‌each‌‌trial‌‌for‌‌the‌‌Hydrosil‌‌tablet‌ ‌
ev

Trial‌ ‌ Initial‌‌Reading‌‌(±
‌ ‌0.05ml)‌ ‌ Final‌‌Reading(‌±0‌ .05ml)‌ ‌ Difference(‌±0‌ .10ml)‌ ‌
ul
at

1‌ ‌ 50‌ ‌ 13.3‌ ‌ 36.7‌ ‌

am

2‌ ‌ 50‌ ‌ 13.9‌ ‌ 36.1‌ ‌

id
va

3‌ ‌ 50‌ ‌ 14.5‌ ‌ 35.5‌ ‌

y
tif

4‌ ‌ 50‌ ‌ 15.8‌ ‌ 34.2‌ ‌

as

Processed‌‌Data:‌ ‌
Cl

Table‌‌2.1:‌‌This‌‌table‌‌shows‌‌the‌‌volume‌‌of‌‌titrant(NaOH)‌‌used‌‌in‌‌total‌‌for‌‌every‌‌tablet‌ ‌
Volume‌‌of‌‌NaOH‌‌consumed‌‌through‌‌titre(mL)‌‌(±‌‌0.1mL)‌ ‌ ‌
Brand‌‌of‌‌antacid‌ ‌ Trial‌‌1‌ ‌ Trial‌‌2‌ ‌ Trial‌‌3‌ ‌ Trial‌‌4‌ ‌ Average‌ ‌ Standard‌‌Deviation‌ ‌
Maalox‌‌Plus‌ ‌ 23.5‌ 21.8‌ 32.4‌ 24.7‌ 25.6‌ 4.69‌
Magsil‌ ‌ 21.6‌ 26.2‌ 29.5‌ 23.7‌ 25.3‌ 3.40‌
Actal‌ ‌ 16.5‌ 26.5‌ 34.7‌ 19.2‌ 24.2‌ 8.16‌
Hydrosil‌ ‌ 36.7‌ 36.1‌ 35.5‌ 34.2‌ 35.6‌ 1.07‌
Table‌‌2.2:‌‌This‌‌table‌‌shows‌‌the‌‌volume‌‌of‌‌HCl(aq)‌‌in‌‌excess‌‌for‌‌every‌‌tablet‌ ‌
Volume‌‌of‌‌HCl(aq)‌‌in‌‌excess(mL)(±‌‌0.1mL)‌ ‌ ‌
Brand‌‌of‌‌antacid‌ ‌ Trial‌‌1‌ ‌ Trial‌‌2‌ ‌ Trial‌‌3‌ ‌ Trial‌‌4‌ ‌ Average‌ ‌ Standard‌‌Deviation‌ ‌
 Downloaded from www.clastify.com by Vaida Matulevičiūtė

6‌ ‌
Maalox‌‌Plus‌ ‌ 23.5‌ 21.8‌ 32.4‌ 24.7‌ 25.6‌ 4.69‌
Magsil‌ ‌ 21.6‌ 26.2‌ 29.5‌ 23.7‌ 25.3‌ 3.40‌
Actal‌ ‌ 16.5‌ 26.5‌ 34.7‌ 19.2‌ 24.2‌ 8.16‌
Hydrosil‌ ‌ 36.7‌ 36.1‌ 35.5‌ 34.2‌ 35.6‌ 1.07‌
Table‌‌2.3:‌‌This‌‌table‌‌shows‌‌the‌‌moles‌‌of‌‌NaOH(aq)‌‌that‌‌reacted‌‌with‌‌the‌‌excess‌‌HCl(aq)‌ ‌
Moles‌‌of‌‌NaOH(aq)(1*10^-3mol)‌ ‌ ‌
Brand‌‌of‌‌antacid‌ ‌ Trial‌‌1‌ ‌ Trial‌‌2‌ ‌ Trial‌‌3‌ ‌ Trial‌‌4‌ ‌ Average‌ ‌ Standard‌‌Deviation‌ ‌
Maalox‌‌Plus‌ ‌ 11.8‌ 10.9‌ 16.2‌ 12.4‌ 12.8‌ 2.34‌
Magsil‌ ‌ 10.8‌ 13.1‌ 14.8‌ 11.9‌ 12.7‌ 1.70‌
Actal‌ ‌ 8.3‌ 13.3‌ 17.4‌ 9.6‌ 12.1‌ 4.08‌

om
Hydrosil‌ ‌ 18.4‌ 18.1‌ 17.8‌ 17.1‌ 17.8‌ 0.53‌

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‌

ai
gm
Table‌‌2.4:‌‌This‌‌table‌‌shows‌‌the‌‌volume‌‌of‌‌HCl(aq)‌‌that‌‌reacted‌‌with‌‌each‌‌tablet‌ ‌
Volume‌‌of‌‌HCl(aq)‌‌that‌‌reacted‌‌with‌‌tablet(mL)(±‌‌0.1mL)‌ ‌

@
Brand‌‌of‌‌antacid‌ ‌ Trial‌‌1‌ ‌ Trial‌‌2‌ ‌ Trial‌‌3‌ ‌ 93 Trial‌‌4‌ ‌ Average‌ ‌ Standard‌‌Deviation‌ ‌
te
Maalox‌‌Plus‌ ‌ 26.5‌ 28.2‌ 17.6‌ 25.3‌ 24.4‌ 4.69‌
iu
ic

Magsil‌ ‌ 28.4‌ 23.8‌ 20.5‌ 26.3‌ 24.8‌ 3.40‌

ev

Actal‌ ‌ 33.5‌ 23.5‌ 15.3‌ 30.8‌ 25.8‌ 8.16‌

ul
at

Hydrosil‌ ‌ 13.3‌ 13.9‌ 14.5‌ 15.8‌ 14.4‌ 1.07‌

am

Table‌‌2.5:‌‌This‌‌table‌‌shows‌‌the‌‌moles‌‌of‌‌HCl(aq)‌‌that‌‌reacted‌‌with‌‌each‌‌tablet‌ ‌
id

Moles‌‌of‌‌HCl(aq)‌‌that‌‌reacted‌‌with‌‌tablet(1*10^-3mol)‌ ‌ ‌
va

Brand‌‌of‌‌antacid‌ ‌ Trial‌‌1‌ ‌ Trial‌‌2‌ ‌ Trial‌‌3‌ ‌ Trial‌‌4‌ ‌ Average‌ ‌ Standard‌‌Deviation‌ ‌

y
tif

Maalox‌‌Plus‌ ‌ 13.3‌ 14.1‌ 8.8‌ 12.7‌ 12.2‌ 2.34‌

as

Magsil‌ ‌ 14.2‌ 11.9‌ 10.3‌ 13.2‌ 12.4‌ 1.70‌

Cl

Actal‌ ‌ 16.8‌ 11.8‌ 7.7‌ 15.4‌ 12.9‌ 4.08‌

Hydrosil‌ ‌ 6.7‌ 7.0‌ 7.3‌ 7.9‌ 7.2‌ 0.53‌
Sample‌‌Calculations:‌ ‌
Here‌‌are‌‌some‌‌sample‌‌calculations:‌ ‌
1. Calculating‌‌the‌‌average‌‌volume‌‌of‌‌NaOH(aq)‌‌consumed‌‌through‌‌titre‌‌by‌‌excess‌‌HCl(aq)‌‌ ‌
With‌‌Maalox‌‌Plus,‌‌the‌‌volumes‌‌of‌‌NaOH(aq)‌‌were‌ ‌23.5,‌‌21.8,‌‌32.4,‌‌24.7‌‌mL‌‌respectively.‌ ‌
Formula:‌‌Average = ∑V olumes4 = 23.5 + 21.8 +4 32.4 + 24.7 = 25.6mL ‌ ‌
All‌‌below‌‌calculations‌‌will‌‌use‌‌the‌‌‌first‌‌trial‌‌of‌‌Magsil‌‌‌as‌‌sample‌‌calculations:‌ ‌
2. Calculating‌‌the‌‌moles‌‌of‌‌NaOH(aq)‌‌required‌‌to‌‌titrate‌‌the‌‌excess‌‌HCl(aq)‌‌solution‌ ‌
Volumes‌‌of‌‌NaOH(aq)‌‌in‌‌the‌‌first‌‌trial‌‌is‌‌21.6mL±1mL(3.s.f)‌ ‌
We‌‌know‌‌that‌‌[N aOH] = 0.5M ‌Therefore,‌‌using‌‌n = C * V :‌ ‌
 Downloaded from www.clastify.com by Vaida Matulevičiūtė

7‌ ‌
21.6 −2
Formula:‌‌nM (N aOH) = C * V ≈ 0.5M * ( 1000 dm3 )
= 0.0108mol = 1.08 * 10 mol (3.s.f)‌‌ ‌
3. Calculating‌‌the‌‌moles‌‌of‌‌excess‌‌HCl(aq)‌‌that‌‌reacted‌‌with‌‌NaOH(aq)‌‌in‌‌titre‌‌ ‌
0.0108mol of‌‌NaOH(aq)‌‌has‌‌reacted.‌‌By‌‌HCl(aq)+NaOH(aq)‌‌→‌‌NaCl(aq)‌‌+‌‌H2‌‌ O(l)‌‌we‌‌see‌‌that‌‌NaOH(aq)‌‌and‌‌
HCl(aq)‌‌reacts‌‌in‌‌a‌‌1:1‌‌ratio,‌‌and‌‌nM (HCl) = nM (N aOH) = 0.0108mol (3.s.f)‌‌ ‌
4. Calculating‌‌the‌‌volume‌‌of‌‌excess‌‌HCl(aq)‌‌that‌‌reacted‌‌with‌‌NaOH(aq)‌‌in‌‌titre‌ ‌
As‌‌concentration‌‌of‌‌HCl(aq)‌‌is‌‌0.5M:‌V = Cn ≈ 0.01080.5
dm3 = 0.0216dm3 = 21.6mL (3.s.f)‌ ‌
5. Calculating‌‌the‌‌moles‌‌of‌‌HCl(aq)‌‌that‌‌reacted‌‌with‌‌active‌‌ingredient‌‌in‌‌tablet‌‌ ‌
As‌‌[HCl] = 0.5M ‌and‌‌initial‌‌volume‌‌of‌‌H Cl = 50mL ,‌‌we‌‌have,‌‌by‌‌n = C * V ‌
50
nM (HCl) initial = C * V = (0.5M ) * ( 1000 dm3 ) = 0.025mol ‌
nM (HCl) reacted = nM (HCl) initial − nM (HCl) excess
nM (HCl) reacted = 0.025 − 0.0108 = 0.0142mol = 1.42 * 10−2 mol ‌
6. Calculating‌‌final‌‌percentage‌‌and‌‌absolute‌‌uncertainty‌‌of‌‌all‌‌measurements‌ ‌

om
There‌‌are‌‌two‌‌instruments‌‌with‌‌uncertainties‌‌that‌‌were‌‌used‌‌in‌‌this‌‌experiment.‌‌The‌‌first‌‌instrument‌‌is‌‌the‌‌

l.c
burette,‌‌which‌‌was‌‌used‌‌to‌‌measure‌‌out‌‌50mL‌‌of‌‌NaOH(aq)‌‌solution‌‌for‌‌titre,‌‌and‌‌the‌‌second‌‌is‌‌the‌‌measuring‌‌

ai
cylinder,‌‌which‌‌was‌‌used‌‌to‌‌measure‌‌50mL‌‌of‌‌HCl(aq)‌‌solution.‌ ‌

gm
%‌‌Uncertainty‌‌of‌‌Burette‌‌= ( Absolute uncertainty of Burette × 2
Raw Data V alue measured
) × 100 = ( 0.05×2
21.6
) × 100 ≈ 0.46% (2.s.f)‌ ‌
%‌‌Uncertainty‌‌of‌‌Cylinder‌‌= ( Absolute uncertainty of Cylinder

@
1
Raw Data V alue measured
) × 100 = ( 50 ) × 100 ≈ 2.00% ‌
93
(*Note‌‌that‌‌uncertainty‌‌of‌‌Burette‌‌is‌‌multiplied‌‌by‌‌2‌‌as‌‌burette‌‌reading‌‌is‌‌taken‌‌twice‌‌each‌‌titre)‌‌ ‌
te
Total‌‌percent‌‌uncertainty‌‌=‌‌ 2.00 + 0.46 = 2.46% ‌
iu

Absolute‌‌uncertainty‌‌for‌‌processed‌‌value‌‌= 14.2 × 2.46 100

= 0.35 mol (2.s.f)‌ ‌
ic

Final‌‌processed‌‌value‌‌with‌‌uncertainty‌‌= 14.2 ± 0.35 mol ‌HCl(aq)‌‌for‌‌every‌‌Magsil‌‌tablet‌ ‌

ev

Table‌‌3.1:‌‌Final‌‌processed‌‌data‌‌table‌‌that‌‌shows‌‌the‌‌moles‌‌of‌‌HCl(aq)‌‌solution‌‌reacted‌‌with‌‌each‌‌tablet,‌‌
ul

with‌‌absolute‌‌uncertainties,‌‌averages‌‌and‌‌standard‌‌deviation‌‌labeled‌ ‌
at

Moles‌‌of‌‌HCl(aq)‌‌that‌‌reacted‌‌with‌‌tablet(1*10^-3mol/tablet)‌ ‌ ‌ Avg‌‌%‌‌
am

Standard‌‌ Uncertainty‌
id

Brand‌‌of‌‌antacid‌ Trial‌‌1‌ ‌ Trial‌‌2‌ ‌ Trial‌‌3‌ ‌ Trial‌‌4‌ ‌ Average‌ ‌ Deviation‌ ‌ for‌‌tablet‌ ‌

va

Maalox‌‌Plus‌ ‌ 13.3‌‌±‌‌0.32‌ 14.1‌‌±‌‌0.35‌ 8.8‌‌±‌‌0.20‌ 12.7‌‌±‌‌0.31‌ 12.2‌‌±‌‌0.29‌ 2.34‌ 2.39‌

y
tif

Magsil‌ ‌ 14.2‌‌±‌‌0.35‌ 11.9‌‌±‌‌0.28‌ 10.3‌‌±‌‌0.24‌ 13.2‌‌±‌‌0.32‌ 12.4‌‌±‌‌0.30‌ 1.70‌ 2.40‌

as
Cl

Actal‌ ‌ 16.8‌‌±‌‌0.44‌ 11.8‌‌±‌‌0.28‌ 7.7‌‌±‌‌0.18‌ 15.4‌‌±‌‌0.39‌ 12.9‌‌±‌‌0.31‌ 4.08‌ 2.41‌

Hydrosil‌ ‌ 6.7‌‌±‌‌0.15‌ 7.0‌‌±‌‌0.16‌ 7.3‌‌±‌‌0.17‌ 7.9‌‌±‌‌0.18‌ 7.2‌‌±‌‌0.16‌ 0.53‌ 2.28‌
From‌‌the‌‌dataset‌‌above,‌‌we‌‌can‌‌see‌‌that‌‌the‌‌average‌‌percentage‌‌uncertainty‌‌for‌‌every‌‌tablet‌‌is:‌ ‌
Average‌‌percentage‌‌uncertainty‌‌=‌‌ 2.39+2.40+2.41+2.28
4 = 2.37% ‌
‌
‌
‌
‌
‌
‌
‌
‌
Graph‌‌1-1:‌‌The‌‌Brand‌‌of‌‌antacid‌‌tablets‌‌vs‌‌the‌‌moles‌‌of‌‌HCl(aq)‌‌neutralised‌‌by‌‌the‌‌tablet‌ ‌
 Downloaded from www.clastify.com by Vaida Matulevičiūtė

8‌ ‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌

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‌

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‌

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‌

gm
Table‌‌4.1:‌‌Literature‌‌values‌‌of‌‌active‌‌ingredients‌‌content‌‌in‌‌each‌‌antacid‌‌tablet‌ ‌

@
(*Note:‌‌Moles‌‌of‌‌active‌‌ingredient‌‌and‌‌moles‌‌of‌‌HCl(aq)‌‌neutralized‌‌are‌‌rounded‌‌to‌‌3.s.f)‌ ‌
93
Antacid‌‌brand‌ ‌ Mass‌‌of‌‌active‌‌ingredient‌ ‌ Moles‌‌of‌‌active‌‌ingredient‌ ‌ Moles‌‌of‌‌HCl(aq)‌‌neutralized/tablet‌ ‌
te
iu

Maalox‌‌Plus‌ ‌ Al(OH)‌3‌:‌‌200mg‌‌=‌‌0.2g‌ ‌ nM(Al(OH)‌3‌)≈‌‌0.00256‌ ‌ 0.0145‌ ‌

ic

Mg(OH)‌2‌:200mg‌‌=‌‌0.2g‌ ‌ nM(Mg(OH)‌2‌)≈‌‌0.00343‌ ‌
ev
ul

Magsil‌ ‌ Al(OH)‌3‌:‌‌200mg‌‌=‌‌0.2g‌ ‌ nM(Al(OH)‌3‌)≈‌‌0.00256‌ ‌ 0.0145‌ ‌

at

Mg(OH)‌2‌:200mg‌‌=‌‌0.2g‌ ‌ nM(Mg(OH)‌2‌)≈‌‌0.00343‌ ‌
am

Actal‌ ‌ Al(OH)‌3‌:‌‌216mg‌‌=‌‌0.216g‌ ‌ nM(Al(OH)‌3‌)≈‌‌0.00277‌ ‌ 0.00831‌ ‌

id
va

Hydrosil‌ ‌ Al(OH)‌3‌:‌‌200mg‌‌=‌‌0.2g‌ ‌ nM(Al(OH)‌3‌)≈‌‌0.00256‌ ‌ 0.0145‌ ‌

Mg(OH)‌2‌:200mg‌‌=‌‌0.2g‌ ‌ nM(Mg(OH)‌2‌)≈‌‌0.00343‌ ‌
y
tif

(‌Search‌‌Drug,‌‌n.d.)‌ ‌
as

Sample‌‌Calculations‌‌to‌‌find‌‌literature‌‌value:‌ ‌
Cl

(*‌‌Below‌‌calculations‌‌will‌‌be‌‌using‌‌the‌‌masses‌‌of‌‌active‌‌ingredient‌‌given‌‌for‌‌the‌‌Actal‌‌tablet)‌‌ ‌
We‌‌are‌‌given‌‌that‌‌there‌‌are‌‌0.216g‌‌of‌‌Aluminium‌‌Hydroxide‌‌in‌‌one‌‌tablet‌‌of‌‌Actal.‌‌We‌‌can‌‌calculate‌‌the‌‌molar‌‌
mass‌‌of‌‌Aluminium‌‌Hydroxide‌‌by‌‌knowing‌‌that‌‌n(Al)‌‌≈‌‌26.98,‌‌n(H)‌‌≈‌‌1.01‌‌and‌‌n(O)‌‌≈‌‌16.‌‌Therefore,‌‌moles‌‌of‌‌
active‌‌ingredient‌‌in‌‌Actal‌‌will‌‌be:‌‌n = MT otal mass
olar mass
= 26.98 +0.216
(1.01+16)×2
≈ 0.002769 ≈ 0.00277 (3.s.f).‌‌Since:‌ ‌
Al(OH)‌3(s)‌+‌‌3HCl‌(aq)‌‌ ‌->‌‌3H‌2‌O‌(l)‌‌ ‌+‌‌AlCl‌3(aq)‌ ‌
We‌‌know‌‌that‌‌n(HCl)‌‌:‌‌n(‌Al(OH)‌3‌)‌‌=‌‌3:1,‌ ‌=>‌ ‌n(HCl)‌‌=‌‌3‌‌× ‌n(Al(OH)‌3‌)‌‌=‌‌0.00831(3.s.f)‌ ‌
‌
8.1‌‌Conclusion‌ ‌
The‌‌aim‌‌of‌‌this‌‌investigation‌‌was‌‌to‌‌examine‌‌the‌‌effectiveness‌‌of‌‌different‌‌brands‌‌of‌‌antacid‌‌tablets,‌‌based‌‌on‌‌
the‌‌amount‌‌of‌‌HCl(aq)‌‌that‌‌each‌‌tablet‌‌was‌‌able‌‌to‌‌neutralize.‌‌The‌‌experiment‌‌is‌‌done‌‌through‌‌back-titration,‌‌
reacting‌‌HCl(aq)‌‌with‌‌the‌‌tablet,‌‌and‌‌then‌‌the‌‌excess‌‌HCl(aq)‌‌titrated‌‌with‌‌NaOH(aq).‌ ‌ ‌
‌
 Downloaded from www.clastify.com by Vaida Matulevičiūtė

9‌ ‌
Referring‌‌to‌‌the‌‌Hypothesis,‌‌my‌‌hypothesis‌‌predicted‌‌that‌‌Actal‌‌will‌‌be‌‌the‌‌most‌‌effective,‌‌as‌‌it‌‌only‌‌contained‌‌
Aluminium‌‌Hydroxide‌‌as‌‌an‌‌active‌‌component.‌‌Assuming‌‌all‌‌else‌‌to‌‌be‌‌constant,‌‌I‌‌believed‌‌that‌‌Aluminium‌‌
Hydroxide‌‌will‌‌neutralise‌‌the‌‌most‌‌HCl(aq).‌‌From‌‌the‌‌data,‌‌it‌‌can‌‌be‌‌seen‌‌that‌‌Actal‌‌indeed‌‌is‌‌the‌‌most‌‌
effective,‌‌as‌‌it‌‌neutralises‌‌the‌‌most‌‌HCl(aq)‌‌solution.‌‌This‌‌can‌‌also‌‌be‌‌observed‌‌through‌‌the‌‌graph,‌‌which‌‌shows‌‌
the‌‌yellow‌‌bar‌‌representing‌‌Actal‌‌to‌‌be‌‌the‌‌one‌‌that‌‌is‌‌able‌‌to‌‌neutralize‌‌the‌‌most‌‌acid.‌‌ ‌
‌
The‌‌data‌‌also‌‌seems‌‌to‌‌suggest‌‌that‌‌Hydrosil‌‌is‌‌significantly‌‌less‌‌effective‌‌in‌‌the‌‌neutralization‌‌of‌‌HCl(aq)‌‌than‌‌
other‌‌tablets,‌‌whilst‌‌Actal,‌‌Magsil‌‌and‌‌Maalox‌‌Plus‌‌all‌‌have‌‌very‌‌similar‌‌efficiency.‌‌This‌‌fact‌‌can‌‌be‌‌
demonstrated‌‌in‌‌the‌‌raw‌‌data‌‌tables‌‌as‌‌well,‌‌where‌‌other‌‌tablets‌‌such‌‌as‌‌Maalox‌‌Plus‌‌and‌‌Magsil‌‌have‌‌the‌‌
burette‌‌final‌‌reading‌‌at‌‌around‌‌25cm‌3‌,‌‌whilst‌‌most‌‌of‌‌Hydrosil’s‌‌final‌‌reading‌‌was‌‌at‌‌around‌‌13cm‌3‌.‌‌This‌‌implies‌‌
that‌‌much‌‌more‌‌HCl(aq)‌‌was‌‌present‌‌in‌‌excess‌‌for‌‌Hydrosil,‌‌as‌‌more‌‌NaOH(aq)‌‌was‌‌required‌‌for‌‌titration.‌ ‌
‌
Despite‌‌the‌‌hypothesis‌‌being‌‌shown‌‌correct‌‌by‌‌my‌‌data,‌‌it‌‌is‌‌evident‌‌that‌‌my‌‌data‌‌does‌‌not‌‌match‌‌with‌‌the‌‌

om
literature‌‌values‌‌for‌‌this‌‌experiment,‌‌which‌‌was‌‌according‌‌to‌‌mims.com,‌‌a‌‌provider‌‌of‌‌medical‌‌information‌‌for‌‌

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healthcare‌‌professionals‌‌and‌‌pharmaceutical‌‌companies.‌‌The‌‌literature‌‌values(the‌‌masses‌‌of‌‌active‌‌ingredient‌‌in‌‌

ai
tablet)‌‌suggested‌‌that‌‌the‌‌effectiveness‌‌of‌‌each‌‌tablet,‌‌except‌‌for‌‌actal,‌‌should‌‌be‌‌the‌‌same,‌‌and‌‌actal‌‌should‌‌be‌‌

gm
significantly‌‌LESS‌‌effective‌‌than‌‌the‌‌others,‌‌rather‌‌than‌‌more.‌‌All‌‌of‌‌these‌‌suggests‌‌that‌‌the‌‌experiment‌‌is‌‌

@
highly‌‌inaccurate‌‌and‌‌there‌‌are‌‌significant‌‌underlying‌‌random‌‌and‌‌systematic‌‌errors‌‌in‌‌the‌‌methodology.‌ ‌
‌ 93
te
Standard‌‌deviation,‌‌denoted‌‌by‌‌σ ,‌‌is‌‌a‌‌number‌‌which‌‌measures‌‌the‌‌spread‌‌and‌‌dispersion‌‌of‌‌a‌‌given‌‌dataset,‌‌
iu

was‌‌shown‌‌in‌‌the‌‌processed‌‌data.‌‌Taking‌‌the‌‌standard‌‌deviation‌‌value‌‌obtained‌‌for‌‌Actal‌‌as‌‌an‌‌example,‌‌we‌‌see‌‌
ic

that‌‌the‌‌distribution‌‌range‌‌of‌‌that‌‌data‌‌was‌‌(12.9 − 4.08, 12.9 + 4.08) = (8.82, 16.98) ,‌‌very‌‌spread‌‌out..‌‌This‌‌

ev

shows‌‌that‌‌the‌‌data‌‌yielded‌‌from‌‌the‌‌experiment‌‌was‌‌neither‌‌accurate‌‌nor‌‌precise.‌ ‌
ul

‌
at

The‌‌fact‌‌that‌‌the‌‌hypothesis‌‌does‌‌not‌‌match‌‌with‌‌the‌‌literature‌‌value‌‌can‌‌be‌‌partly‌‌explained‌‌by‌‌the‌‌initial‌‌
am

assumption‌‌that‌‌each‌‌tablet‌‌had‌‌the‌‌same‌‌mass‌‌of‌‌active‌‌ingredient‌‌being‌‌false.‌‌It‌‌can‌‌be‌‌easily‌‌seen‌‌with‌‌the‌‌
id

initial‌‌measurements‌‌of‌‌tablet‌‌mass(1.3g,‌‌1g,‌‌0.6g‌‌and‌‌0.7g)‌‌and‌‌literature‌‌values,‌‌that‌‌the‌‌mass‌‌and‌‌percentage‌‌
va

composition‌‌of‌‌each‌‌antacid‌‌tablet‌‌are‌‌not‌‌the‌‌same.‌‌Therefore,‌‌although‌‌Actal‌‌only‌‌had‌‌Aluminium‌‌Hydroxide‌‌
y

as‌‌active‌‌ingredient,‌‌the‌‌assumption‌‌that‌‌all‌‌is‌‌constant‌‌in‌‌the‌‌hypothesis‌‌is‌‌not‌‌true,‌‌and‌‌Actal‌‌has‌‌significantly‌‌
tif

less‌‌of‌‌the‌‌active‌‌ingredient‌‌mass‌‌compared‌‌to‌‌other‌‌tablets,‌‌making‌‌Actal‌‌the‌‌least‌‌effective.‌ ‌ ‌
as

‌
Cl

The‌‌existence‌‌of‌‌systematic‌‌errors‌‌can‌‌also‌‌be‌‌seen‌‌through‌‌the‌‌calculation‌‌of‌‌percentage‌‌error.‌‌We‌‌see‌‌that:‌ ‌
P ercentage error = ∣Literature VLiterature
alue − Experimental V alue∣
V alue
‌
Table‌‌5:‌‌Percentage‌‌error‌‌of‌‌each‌‌tablet‌‌calculated‌‌against‌‌the‌‌literature‌‌value‌ ‌
Antacid‌‌brand‌ ‌ Experimental‌‌Value‌ ‌ Literature‌‌value‌ ‌ %‌‌Percentage‌‌Error‌ ‌
(1*10^-3‌‌mol‌‌HCl/tablet)‌ ‌ (1*10^-3mol‌‌HCl/tablet)‌ ‌

Maalox‌‌Plus‌ ‌ 12.2‌ ‌ 14.5‌ ‌ 15.9‌ ‌

Magsil‌ ‌ 12.4‌ ‌ 14.5‌ ‌ 14.5‌ ‌

Actal‌ ‌ 12.9‌ ‌ 8.31‌ ‌ 55.2‌ ‌

Hydrosil‌ ‌ 7.2‌ ‌ 14.5‌ ‌ 50.3‌ ‌

Downloaded from www.clastify.com by Vaida Matulevičiūtė

10‌ ‌
To‌‌conclude,‌‌it‌‌is‌‌evident‌‌that‌‌the‌‌systematic‌‌errors‌‌have‌‌a‌‌greater‌‌impact‌‌than‌‌the‌‌random‌‌errors,‌‌since‌‌the‌‌
overall‌‌percentage‌‌error‌‌of‌‌all‌‌4‌‌tablets‌‌are‌‌higher‌‌than‌‌the‌‌average‌‌percentage‌‌uncertainty‌‌of‌‌the‌‌measurements‌‌
for‌‌each‌‌tablet.‌‌It‌‌appears‌‌that‌‌the‌‌measurements‌‌of‌‌the‌‌effectiveness‌‌of‌‌antacid‌‌tablets‌‌Maalox‌‌Plus‌‌and‌‌Magsil‌‌
had‌‌a‌‌much‌‌higher‌‌degree‌‌of‌‌accuracy‌‌compared‌‌to‌‌Actal‌‌and‌‌Hydrosil,‌‌shown‌‌through‌‌the‌‌much‌‌lower‌‌
percentage‌‌error.‌‌In‌‌the‌‌evaluation,‌‌possible‌‌sources‌‌of‌‌uncertainties‌‌will‌‌be‌‌listed‌‌and‌‌went‌‌through.‌ ‌
‌
‌Evaluation:‌‌ ‌
Note:‌‌All‌‌errors‌‌are‌‌ranked:‌‌most‌‌significant‌‌at‌‌the‌‌top‌‌and‌‌least‌‌significant‌‌at‌‌the‌‌bottom‌ ‌
Errors‌‌in‌‌the‌‌ Impact‌‌on‌‌Data‌ ‌ Improvement‌ ‌
Experiment‌ ‌

(Systematic‌‌error)‌‌ ‌ To‌‌measure‌‌accurately,‌‌the‌‌meniscus‌‌must‌‌be‌‌at‌‌ For‌‌all‌‌measurements:‌ ‌

Reading‌‌of‌‌the‌‌ eye-level,‌‌and‌‌the‌‌reading‌‌must‌‌be‌‌taken‌‌at‌‌the‌‌ - The‌‌reading‌‌must‌‌be‌‌

om
meniscus‌‌from‌‌the‌‌ centre‌‌of‌‌the‌‌meniscus,‌‌rather‌‌than‌‌at‌‌the‌‌leftmost‌‌ taken‌‌from‌‌eye-level‌ ‌
peak/tip‌‌on‌‌the‌‌left‌‌ or‌‌rightmost‌‌peak‌‌or‌‌trough.‌‌As‌‌this‌‌method‌‌of‌‌ - The‌‌reading‌‌must‌‌be‌‌

l.c
and‌‌right‌‌rather‌‌than‌‌ reading‌‌was‌‌not‌‌explicitly‌‌stated‌‌in‌‌the‌‌ taken‌‌with‌‌the‌‌centre‌‌of‌‌

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at‌‌concave‌‌valley.‌ ‌ methodology‌‌of‌‌this‌‌experiment,‌‌it‌‌would‌‌have‌‌led‌‌ the‌‌meniscus‌ ‌

gm
to‌‌inconsistent‌‌readings‌‌in‌‌the‌‌volume‌‌of‌‌ This‌s‌ hould‌‌be‌‌specified‌‌in‌‌the‌‌

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NaOH(aq)‌‌and‌‌HCl(aq)‌‌solutions,‌‌which‌‌are‌‌ methodology‌‌as‌‌well.‌‌ ‌
93
critical‌‌to‌‌the‌‌accuracy‌‌of‌‌the‌‌value‌‌of‌‌dependent‌‌
variable.(‌How‌‌to‌‌Read‌,‌‌2017).‌‌ ‌
te
iu

(Systematic‌‌error)‌‌ ‌ In‌‌this‌‌experiment,‌‌the‌‌burette‌‌was‌‌closed‌‌ Titrate‌‌the‌‌mixture‌‌more‌‌slowly‌‌

ic

Colour‌‌change‌‌in‌‌ whenever‌‌the‌‌solution‌‌showed‌‌the‌‌slightest‌‌shade‌‌ to‌‌get‌‌more‌‌accuracy‌‌and‌‌

ev

indicator‌‌was‌‌ of‌‌pink.‌‌The‌‌notion‌‌of‌‌the‌‌“slightest‌‌shade”‌‌was‌‌ precision.‌T ‌ itrate‌‌the‌‌NaOH(aq)‌‌

ul

gradual,‌‌rather‌‌than‌‌ ill-defined,‌‌for‌‌some‌‌trials‌‌NaOH(aq)‌‌was‌‌stopped‌‌ in‌‌steps,‌‌5mL‌‌at‌‌a‌‌time,‌‌opening‌‌

at

abrupt.‌‌Unclear‌‌ at‌‌a‌‌very‌‌faint‌‌hue,‌‌whilst‌‌others‌‌were‌‌stopped‌‌ and‌‌closing‌‌the‌‌burette‌‌valve.‌‌

am

endpoint‌‌error‌ ‌ until‌‌a‌‌very‌‌noticeable‌‌colour‌‌change.‌‌The‌‌ Wait‌‌10‌‌seconds‌‌in‌‌order‌‌to‌‌give‌‌

reaction‌‌may‌‌also‌‌not‌‌have‌‌fully‌‌neutralised‌‌at‌‌ the‌‌solution‌‌time‌‌to‌‌fully‌‌react‌‌
id

experimental‌‌endpoint,‌‌as‌‌we‌‌did‌‌not‌‌wait‌‌for‌‌the‌‌ before‌‌a‌‌new‌‌titre.‌‌Stop‌‌the‌‌
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solution‌‌to‌‌change‌‌colour‌‌completely.‌(Carpenter,‌ titration‌‌whenever‌‌the‌‌color‌‌
y

2018)‌ ‌ changes‌‌completely.‌‌ ‌
tif
as

(Systematic‌‌error)‌‌ ‌ The‌‌lab‌‌technicians‌‌kindly‌‌prepared‌‌the‌‌0.5M‌‌ Unavoidable‌

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Potential‌‌impurity‌‌ HCl(aq)‌‌and‌‌0.5M‌‌NaOH(aq)‌‌solutions‌‌for‌‌us‌‌to‌‌ For‌‌future‌‌investigations‌ ‌

or‌‌inaccuracy‌‌with‌‌ use.‌‌Although‌‌in‌‌the‌‌calculations‌‌of‌‌percentage‌‌ - Try‌‌to‌p
‌ repare‌‌the‌‌lab‌‌
the‌‌concentration‌‌of‌‌ uncertainty,‌‌0‌‌was‌‌used‌‌for‌‌the‌‌uncertainty‌‌of‌‌the‌‌ equipments‌‌with‌‌more‌‌
the‌‌acids‌‌and‌‌bases‌‌ concentration,‌‌it‌‌is‌‌still‌‌possible‌‌that‌‌the‌‌process‌‌of‌‌ precise‌i‌nstruments‌ ‌
provided‌ ‌ making‌‌the‌‌solution‌‌was‌‌not‌‌fully‌‌accurate.‌‌The‌‌
molarity‌‌being‌‌either‌‌too‌‌high‌‌or‌‌too‌‌low‌‌would‌‌
have‌‌been‌‌able‌‌to‌‌cause‌‌a‌‌shift‌‌in‌‌all‌‌experimental‌‌
data,‌‌influencing‌‌the‌‌accuracy.‌ ‌

(Random‌‌error)‌‌ ‌ Similar‌‌to‌‌the‌‌above,‌‌human‌‌reaction‌‌time‌‌could‌‌ Use‌‌a‌‌professional‌‌camera‌‌which‌‌

Human‌‌error:‌‌ have‌‌also‌‌influenced‌‌the‌‌endpoint‌‌of‌‌titration‌‌with‌‌ can‌‌take‌‌videos‌‌with‌‌high‌‌FPS,‌‌
Burette‌‌may‌‌not‌‌ NaOH(aq).‌‌It‌‌is‌‌possible‌‌for‌‌excess‌‌NaOH(aq)‌‌to‌‌ which‌‌can‌‌be‌‌replayed‌‌and‌‌tell‌‌of‌‌
have‌‌been‌‌closed‌‌at‌‌ flow‌‌into‌‌flask‌‌as‌‌a‌‌result‌‌of‌‌the‌‌burette‌‌closed‌‌too‌‌ the‌‌exact‌‌endpoint‌‌of‌‌titration.‌‌ ‌
the‌‌exact‌‌right‌‌time‌ ‌ late.‌ ‌ ‌
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11‌ ‌
(Random‌‌error)‌‌ ‌ Leftover‌‌drops‌‌of‌‌acid/base‌‌and‌‌water‌‌may‌‌still‌‌ Take‌‌time‌‌to‌‌empty‌‌and‌‌clean‌‌the‌‌
Contamination‌‌of‌‌ exist‌‌on‌‌the‌‌glass‌‌walls‌‌of‌‌the‌‌burette‌‌or‌‌the‌‌ conical‌‌flask‌‌and‌‌burette‌‌
burette‌‌and‌‌conical‌‌ conical‌‌flask‌‌after‌‌each‌‌trial,‌‌as‌‌neither‌‌were‌‌dried‌‌ thoroughly‌‌after‌‌each‌‌trial.‌‌Leave‌‌
flask.‌‌ ‌ and‌‌washed‌‌thoroughly‌‌after‌‌each‌‌trial.‌‌This‌‌can‌‌ the‌‌conical‌‌flask‌‌to‌‌dry‌‌and‌‌rinse‌‌
influence‌‌the‌‌real‌‌amount‌‌of‌‌acid‌‌and‌‌base‌‌used‌‌ the‌‌burette‌‌with‌‌NaOH(aq)‌‌
for‌‌titration,‌‌thereby‌‌creating‌‌variance‌‌in‌‌the‌‌ solution‌‌to‌‌remove‌‌dropets‌‌
experimental‌‌data.‌ ‌ ‌ adhering‌‌to‌‌the‌‌glass‌‌walls.‌‌ ‌

(Random‌‌error)‌‌ ‌ A‌‌spatula‌‌was‌‌used‌‌to‌‌remove‌‌the‌‌grinded‌‌antacid‌‌ Be‌‌more‌‌patient‌‌with‌‌the‌‌

Incomplete‌‌removal‌‌ tablet‌‌from‌‌the‌‌mortar‌‌and‌‌pestle‌‌bowl.‌‌This‌‌ removal‌‌of‌‌the‌‌bits‌‌from‌‌the‌‌
of‌‌grinded‌‌antacid‌‌ method‌‌was‌‌not‌‌accurate,‌‌as‌‌the‌‌tablet‌‌tends‌‌to‌‌ mortar‌‌bowl‌‌using‌‌the‌‌spatula.‌‌
tablet‌‌from‌‌mortar‌‌ stick‌‌and‌‌is‌‌hard‌‌to‌‌remove‌‌thoroughly.‌‌This‌‌fact‌‌ Perhaps‌‌use‌‌a‌‌knife‌‌to‌‌scrape.‌‌
bowl‌ ‌ could‌‌alter‌‌the‌‌mass‌‌of‌‌active‌‌ingredient‌‌reacted,‌‌ Clean‌‌the‌‌mortar‌‌and‌‌pestle‌‌after‌‌
which‌‌can‌‌negatively‌‌impact‌‌the‌‌experimental‌‌ conducting‌‌each‌‌trial,‌‌to‌‌ensure‌‌

om
accuracy.‌ ‌ ‌ accuracy‌‌of‌‌the‌‌next‌‌trial.‌‌ ‌

l.c
(Random‌‌error)‌‌ ‌ Based‌‌on‌‌collision‌‌theory,‌‌we‌‌know‌‌that‌‌the‌‌higher‌‌ Unavoidable,‌‌as‌‌there‌‌will‌‌

ai
The‌‌temperature‌‌ the‌‌temperature‌‌of‌‌the‌‌reactants,‌‌the‌‌faster‌‌the‌‌rate‌‌ always‌‌be‌‌fluctuations‌‌in‌‌

gm
could‌‌have‌‌had‌‌an‌‌ of‌‌reaction‌‌as‌‌the‌‌individual‌‌particles‌‌will‌‌have‌‌ temperature.‌‌Use‌‌a‌‌thermometer‌‌
effect‌‌on‌‌the‌‌speed‌‌ more‌‌kinetic‌‌energy‌‌and‌‌a‌‌higher‌‌chance‌‌of‌‌ when‌‌conducting‌‌the‌‌experiment.‌‌

@
of‌‌the‌‌reactions‌ ‌ colliding‌‌with‌‌each‌‌other.‌‌Therefore,‌‌a‌‌change‌‌in‌‌ Conduct‌‌the‌‌two‌‌reactions‌‌in‌‌a‌‌
93
temperature‌‌due‌‌to‌‌a‌‌hotter/colder‌‌day‌‌will‌‌ confined,‌‌isolated‌‌system‌‌where‌‌
te
negatively‌‌influence‌‌the‌‌accuracy‌‌of‌‌experiment‌ ‌ the‌‌energy‌‌change‌‌is‌‌minimised.‌ ‌
iu

‌
ic

Whilst‌‌it‌‌is‌‌acknowledged‌‌that‌‌changing‌‌the‌‌above‌‌points‌‌may‌‌improve‌‌the‌‌accuracy‌‌and‌‌precision‌‌of‌‌the‌‌
ev

experiment,‌‌it‌‌may‌‌still‌‌not‌‌be‌‌enough‌‌to‌‌address‌‌the‌‌underlying‌‌flaws‌‌of‌‌the‌‌methodology,‌‌and‌‌may‌‌not‌‌be‌‌
ul
at

sufficient‌‌to‌‌guarantee‌‌that‌‌the‌‌percentage‌‌error‌‌of‌‌the‌‌experiment‌‌will‌‌be‌‌lower‌‌than‌‌the‌‌percentage‌‌uncertainty.‌ ‌
am

‌
‌Extension:‌‌ ‌
id

A‌‌possible‌‌extension‌‌to‌‌this‌‌investigation,‌‌assuming‌‌the‌‌exact‌‌same‌‌experimental‌‌setup‌‌and‌‌equipments‌‌used,‌‌
va

could‌‌be‌‌to‌‌investigate‌‌the‌‌effectiveness‌‌of‌‌a‌‌wide‌‌variety‌‌of‌‌antacid‌‌tablets‌‌that‌‌have‌‌a‌‌range‌‌of‌‌different‌‌costs.‌‌
y
tif

The‌‌research‌‌question‌‌would‌‌therefore‌‌be‌‌on‌‌the‌‌lines‌‌of:‌ ‌“How‌‌does‌‌the‌‌cost‌‌of‌‌antacid‌‌tablets‌‌influence‌‌the‌‌
as

effectiveness‌‌of‌‌the‌‌tablet?”‌‌This‌‌investigation‌‌would‌‌be‌‌a‌‌more‌‌developed‌‌investigation‌‌as‌‌it‌‌would‌‌have‌‌
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enhanced‌‌practical‌‌use,‌‌since‌‌many‌‌consumers‌‌of‌‌antacid‌‌tablets‌‌would‌‌most‌‌likely‌‌be‌‌interested‌‌in‌‌whether‌‌or‌‌
not‌‌a‌‌more‌‌expensive‌‌tablet‌‌would‌‌be‌‌more‌‌effective.‌‌The‌‌new‌‌investigation‌‌also‌‌is‌‌more‌‌meaningful‌‌as‌‌it‌‌has‌‌
the‌‌possibility‌‌of‌‌breaking‌‌misconceptions.‌‌For‌‌example,‌‌that‌‌the‌‌more‌‌expensive‌‌antacids‌‌are‌‌“better”,‌‌when‌‌
that‌‌may‌‌not‌‌necessarily‌‌be‌‌the‌‌case.‌‌ ‌
‌

‌
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12‌ ‌
References:‌ ‌

Carpenter,‌‌M.‌‌E.‌‌(2018,‌‌March‌‌13).‌E
‌ rrors‌‌in‌‌Titration‌‌Experiments‌.‌‌Retrieved‌‌October‌2‌ 3,‌‌2020,‌‌from‌‌

https://sciencing.com/errors-titration-experiments-8557973.html‌ ‌

Clark,‌‌J.‌‌(2000).‌E
‌ LECTRONEGATIVITY‌.‌‌Retrieved‌‌October‌‌20,‌‌2020,‌‌from‌‌

https://www.chemguide.co.uk/atoms/bonding/electroneg.html‌ ‌

Dunn,‌‌K.,‌‌&‌‌Chappell,‌‌C.‌‌(2020,‌‌August‌‌16).‌N
‌ eutralization‌.‌‌Retrieved‌‌October‌‌20,‌‌2020,‌‌from‌‌

om
l.c
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_‌

ai
gm
Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acid%2F%2FBase_Reactions/Neutralizatio‌

@
n‌ ‌
93
te
‌
iu
ic

Find‌‌Drugs‌‌&‌‌Conditions‌.‌‌(n.d.).‌‌Retrieved‌‌October‌‌20,‌‌2020,‌‌from‌‌https://www.drugs.com/‌ ‌
ev
ul

Helmenstien,‌‌A.‌‌M.‌‌(2019,‌‌October‌‌21).‌D
‌ issociation‌‌Reaction‌‌Definition‌‌and‌‌Examples‌.‌‌Retrieved‌‌October‌2‌ 0,‌‌
at
am

2020,‌‌from‌‌https://www.thoughtco.com/definition-of-dissociation-reaction-and-examples-605038‌ ‌
id

‌
va
y

How‌‌to‌‌Dispose‌‌of‌‌Hydrochloric‌‌Acid‌.‌‌(2018,‌‌April‌‌10).‌‌Retrieved‌‌October‌‌22,‌‌2020,‌‌from‌‌
tif
as

https://sciencing.com/dispose-hydrochloric-acid-8419934.html‌ ‌
Cl

How‌‌to‌‌Read‌‌a‌‌Meniscus‌‌in‌‌Chemistry‌.‌‌(2017,‌‌November‌‌21).‌‌Retrieved‌‌October‌‌23,‌‌2020,‌‌from‌‌

https://www.westlab.com/blog/2017/11/21/how-to-read-a-meniscus-in-chemistry#:~:text=What%20is%20Meni‌

scus%3F,the%20wall%20of%20the%20container.‌ ‌

Hydrochloric‌‌acid‌.‌‌(2020,‌‌October‌‌10).‌‌Retrieved‌‌October‌‌20,‌‌2020,‌‌from‌‌

https://pubchem.ncbi.nlm.nih.gov/compound/Hydrochloric-acid‌ ‌

‌
Downloaded from www.clastify.com by Vaida Matulevičiūtė

13‌ ‌
Indigestion‌.‌‌(n.d.).‌‌Retrieved‌‌October‌‌20,‌‌2020,‌‌from‌‌https://www.webmd.com/heartburn-gerd/indigestion#1‌ ‌

Search‌‌Drug‌‌Information,‌‌Images‌‌&‌‌Medical‌‌News‌.‌‌(n.d.).‌‌Retrieved‌‌October‌‌23,‌‌2020,‌‌from‌‌

https://www.mims.com/hongkong‌ ‌

Speight,‌‌J.‌‌G.‌‌(2017).‌‌Industrial‌‌inorganic‌‌chemistry.‌E
‌ nvironmental‌‌Inorganic‌‌Chemistry‌‌for‌‌Engineers‌.‌‌

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/hydrochloric-acid‌ ‌

om
l.c
Stomach‌‌Acid‌.‌‌(n.d.).‌‌Retrieved‌‌October‌‌20,‌‌2020,‌‌from‌‌

ai
gm
https://ib.bioninja.com.au/options/option-d-human-physiology/d2-digestion/stomach-acid.html‌ ‌

@
‌
93
te
Strength‌‌of‌‌Bases‌.‌‌(n.d.).‌‌Retrieved‌‌October‌‌20,‌‌2020,‌‌from‌‌
iu
ic

https://courses.lumenlearning.com/boundless-chemistry/chapter/strength-of-bases/‌ ‌
ev
ul

‌
at
am

Titration‌.‌‌(2019,‌‌June‌‌23).‌‌Retrieved‌‌October‌‌21,‌‌2020,‌‌from‌‌
id

https://chem.libretexts.org/Bookshelves/Ancillary_Materials/Demos_Techniques_and_Experiments/General_La‌
va
y

b_Techniques/Titration‌ ‌
tif
as

‌
Cl