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Determine the Acid Concentration of a Household Acid. - Coggle Diagram
Determine the Acid Concentration of a Household Acid.
What is an acid?
A molecule that is a proton donor.
What are the types of acids?
Brønsted-Lowry acid
Must contain hydrogen
A proton donor
Lewis acid
Electron pair reciever
Molecule does not require a hydrogen atom
What are common household acids?
Yogurt
lactic acid
Will not use in experiment, as the liquid is too viscous to dilute correctly.
Citrus fruits
Could use in experiment, as it is abundant and wont spoil if unrefridgerated.
Citric acid
apples
malic acid
Unlikely to use, as it is difficult to juice an apple
Milk?
lactic acid
Unlikely to use, as the milk will need to be refrigerated for several hours before the experiment.
Batteries
The electrolyte is the acid
Will not use, as it is too difficult to safely remove the electrolyte
Chemical properties
Citric acid
Highly water soluble due to polarity from functional groups
One hydroxyl group
3 carboxyl groups
Citric acid is stronger than malic acid, as there are more carboxyl groups
C6H8O7
lactic acid
Water soluble
carboxylic acid group
hydroxy group
CH3CH(OH)COOH
malic acid
HIghly water soluble due to polarity from functional groups
One hydroxy group
two carboxylic groups
Hydroxyl groups also participates in hydrogen bonding
Carbonyl is a hydrogen bond acceptor and donor
C4H6O5
Method & Materials
Variables
The concentration of the standard solution
Indicator options
Methyl orange
Used for stronger acidic solutions and is effective betweeen pH 3.1 - 4.4
Red at pHs roughly 2 and below, yellow at PHs 4 and above. Orange between 3.1 & 4.4
Phenopthalein
Effective for solutions between pH 8.3 - 10.0
Bromothymol blue
Commonly used for carbonic acid/carbon dioxide presence in a liquids
Normally used for substances that have a pH near 7 (weak acids)
Yellow at pH 6 and below, changes to blue at roughly pH 7.6 and above. Goes green between pH 6.6 and 7. In titration prac, aiming for green as you will get closer to neutral
Effecive range between pHs 6.0 and 7.6
Will use as it has the lowest range of pHs that the desired pH lies within
Univeral indicator
Effective for all pH ranges
Phenol Red
Effective between pHs 6.4 - 8.0
Yellow at pH 6.4 and below, deep pink at pH 8 and above. Lighter, almost creamy pink between pH 6.4 and 8
Base using
ammonia
Due to it being a weak base, getting a more accurate pH will be easier.
Materials
1x 100ml volumetric flask
1x ceramic tile
1x volumetric pipette filler
1x 200mL beaker
1x 20ml volumetric pipette
1x burette
1x conical flask
1x clamp stand
Base options
Strong
NaOH
KOH
Their ionic bond means when dissolved in an aqueous solution, the two oppositly charged atoms break the bond and become free-floating ions. The negatively charged ions are proton acceptors.
Weak
ammonia
weak as the nitrogen atom has a free electon pair that readily accepts a proton (H+ ion).
when dissolved in water, ammonia aquires hydrogen ions from the water.
trimethyl ammonia