Finals Prt. 1 Flashcards
T or F| Titration is faster than gravimetric
True
T or F| Gravimetric has less errors/ sacrifice in accuracy and precision than Titration (Volumetric)
False - Mas daghan errors sa Gravi
T or F| Titration is more expensive than Gravimetric
False - it is less expensive because it uses little materials
definit, reproducible relationship exists between the reacting substances.
Stoichiometric
A reaction that goes to completion when an amount of titrant equivalent to the amount of analyte present is added.
Quantitative
Why is titration fast? Slow reactions are not suitable in titration because?
It is difficult to estimate the equivalence point same as when reaction don’t proceed to completion.
Pregnancy Testing (Quanti or Quali)
Quanti - applies titration to a blood sample to measure the specific amount of hCG present in the blood.
Blood Sugar Testing (Quanti or Quali?)
Quanti - measure the amount of glucose in their blood by using a small portable machine called a blood glucose meter.
Aquarium Water Testing (Quanti or Quali?)
Quanti- monitor changes in water conditions, home test kits are sold containing chemicals to test the pH level of water
Pharmacists use ______ to achieve a desired mix of compound drugs.
titration
Doctors will often employ ______ to determine the correct proportion of different medicines in an intravenous drip.
titration
Titration is used in the food industry.
● to test free ________ content, _________ and trace amounts of water.
● to determine the estimated chain length of _______ in a fat.
fatty acid, unsaturated fatty acids
fatty acids
Titration is used in the food industry.
to test for the amount of _____ or _____, and the concentration of vitamin ___ or ____, in a product
salt or sugar
C or E
Titration is used in the food industry.
to test the product’s readiness for consumption in _____ and ______production.
wine and cheese
Titration can be employed in biology labs, where it is used to determine the proper concentration of chemicals to _________ test animals.
anesthetize
reaction occurs when equimolar solutions of acids and bases react and create a neutral solution.
neutralization
_________ neutralize excess ________ to form water and magnesium
Hydroxide ions (OH-) / hydrogen ions (H+)
• Is the solution added from the burette.
TITRANT
Its concentration is known
TITRANT
• Is the sample to be titrated.
ANALYTE
It has an unknown concentration.
ANALYTE
• Is the point at which the amount of acid and base present exactly neutralizes one another.
EQUIVALENCE POINT
• Is a substance that is generally added to the solution in the receiving vessel an which undergoes some sort of color change when reaction is over.
INDICATOR
• Is the point when the indicator changes color.
END POINT OF TITRATION
The _____________ on a titration curve is whe the moles of acid are equal to the moles of base.
equivalence point
When the equivalence point is reached the reaction is called
neutralization reaction
3 TYPES OF ACID-BASE TITRATION
Strong Acid-Strong Base Titration
Strong Acid-Weak Base Titration
Weak Acid-Strong Base Titration
: When sample is an acid
Acidimetry
: When sample is a base
Alkalimetry
- is the center of all titrations and it should be standardized first before you will use it, thus the name standard solution
Titrant
PROPERTIES of titrant
o Be sufficiently stable
o React rapidly to the analyte
o React more or less completely with the analyte
o Undergo a selective reaction with the analyte
- acid titrant most commonly used
HYDROCHLORIC ACID
Why is HCl commonly used as a titrant?
Advantages:
• it is a strong acid
• dilute solutions are very stable
• very little oxidizing and reducing power
• chloride ions do from precipitates with other cations
T or F| chloride ions from precipitates with other cations
True
Commonly used acid titrants
HYDROCHLORIC ACID
DILUTE SOLUTIONS OF PERCHLORIC ACID
DILUTE SOLUTIONS OF SULFURIC ACID
o contains secondary hydrogen
o forms insoluble sulfates with other common cations
DILUTE SOLUTIONS OF SULFURIC ACID
There are no available primary grade reagents for _____ titrants and therefore must be standardized
base titrants
Why must base titrants be standardized?
Because there are no available primary grade reagents for base titrants
Common base titrants
NaOH
KOH
- used almost exclusively for titrating acids in aq. Soln
NaOH
- as substitute for NaOH
KOH
is a highly purified compound that serves as a reference material in titrations and in other analytical methods.
Primary Standard
Important requirements for primary standard;
o High purity
o Atmospheric stability
o Absence of hydrate water
o Modest cost
o Reasonable solubility
o Reasonably large molar mass
PRIMARY STANDARDS FOR ACIDS
Sodium carbonate, Na2CO3
Sodium tetraborate, Na2B4O 710 H2O
Commonly used for standardizing acid solution
Sodium Carbonate
PRIMARY STANDARDS FOR BASE
Potassium hydrogen phthalate, KHC8H4O4
Sulfamic acid, H ₂ NSO ₂ H
Tris(hydroxymethyl)aminomethane, (HOCH2)3CNH2
Are substances whose solutions change color due to changes in pH.
Indicators
________ indicators are usually compounds of complex structure, and like a dyestuff in character. They are usually either weak acids or weak bases.
Acidimetric
Indicators that are commonly used in acid-base titration are (3)
methyl orange
methyl red
phenolphthalein
Methyl Orange
3.0 - 4.4
Phenolphthalein
8.2 - 10.0
CHOOSING THE SUITABLE INDICATOR
This choice ensures that the pH at the __________ will fall within the range over which indicator changes color
equivalent point
pH RANGES FOR INDICATOR:
Strong Acid-Strong Base
-End Point pH Range
-Suitable indicator
3-10
Any Indicator
pH RANGES FOR INDICATOR:
Weak Acid-Strong Base
-End Point pH Range
-Suitable indicator
7-11
Phenolphthalein, thymol blue (8.0-9.6)
pH RANGES FOR INDICATOR:
Strong Acid-weak Base
-End Point pH Range
-Suitable indicator
3-7
Methyl orange, methyl red
pH RANGES FOR INDICATOR:
Weak Acid-Weak Base
-End Point pH Range
-Suitable indicator
None
can be used to monitor the pH during the titration instead of relying solely on indicators.
pH meters or pH electrodes
This provides more accurate and precise measurements of pH throughout the titration process.
pH meters or pH electrodes
pH at equivalence point in all strong acid-strong base titrations falls to ___ which is neutral.
7
pH at equivalence point of the titration of strong acids-bases is constant at __, you may choose an indicator that changes its color on pH __ like methyl orange, phenolphthalein, or thymol blue.
7
indicators that changes its color on pH 7 like
methyl orange
phenolphthalein
thymol blue.
METHYL ORANGE:
______ in base
______ in acid
endpoint is _____ to _____
yellow
red
peach to orange
PHENOLPHTHALEIN:
_____in base
_______ in acid
endpoint is ___________
fuchsia
colorless
very light pink
is preferred for cleaning burettes due to its purity, minimal residue, prevention of reactions, consistency, and promotion of accuracy and precision. It ensures that the burette remains clean, free from contaminants, and in optimal condition for accurate measurements in subsequent experiments or titrations.
distilled water
is used to accurately measure and dispense the titrant (the solution of known concentration) into the analyte solution during the titration.
Burette
is used to hold the burette in a vertical position during the titration. It ensures stability and allows for easy control and adjustment of the burette height.
burette stand or clamp
is a glass container that holds the analyte solution, the substance whose concentration is being determined.
titration flask
is a substance that undergoes a color change or other noticeable change at or near the endpoint of the titration.
indicator
helps in visually detecting the completion of the reaction between the analyte and the titrant.
indicator
allows for precise control of the flow rate of the titrant from the burette into the titration flask.
burette tip or stopcock
