Acids and bases - Ch12,13 Flashcards
Arrhenius acid
Substance that dissociates in water to give H+ ions
Arrhenius weak acid
Substance that only slightly dissociates in water to give H+ ions
Arrhenius strong acid
Substance that almost completely dissociates in water to give H+ ipns
Arrhenius base
Substance that dissociates in water to give OH- ions
Arrhenius weak base
Substance that only slightly dissociates in water to give OH- ions
Arrhenius strong base
Substance that almost completely dissociates in water to give OH- ions
Mono basic acid
Has only one H+ to donate
HCl
Dibasic acid
Has two H+ to donate
H2SO4
Hydronium ion H3O+
It is a H+
Alkali
A base that is soluble in water
All alkalis are bases, all bases are not alkali because not all bases dissolve in water
Shortcoming of arrhenius
- H+ don’t exist in solution, H3O+ exists
- Not all acid-base reactions require water
Brownstead lowry acid
Proton donor
Strong BL acid
Good proton donor
Weak BL acid
Poor proton donor
Brownstead lowry base
Proton acceptor
Strong BL base
Good proton acceptor
Weak BL base
Poor proton acceptor
Amphoteric, amphiprotic
Substance that can act as an acid or a base
H2O
Conjugate acid
Formed when a base accepts a proton
Conjugate base
Formed when an acid donates a proton
Conjugate pair
Acid and base that differ by one proton
Neutralization
Acid + base –> salt + water
Limestone
Used on chimneys, neutralize acidity
Standard solution
Solution whose concentration is accurately known
Primary standard
A substance that can be obtained in a stable, pure and solid form so that it can be weighed out and dissolved in water to give a solution of accurately known concentration
To standardise a solution
To accurately find the concentration of a solution by doing a titration
Exp. To standardise a solution of Na2CO3 (sodium carbonate):
- Accurately weigh out a known mass of anhydrous sodium carbonate on a clock glass using a balance
- Transfer with washings with deionised water to clean beaker
- Stir with a clean glass rod until fully dissolved
- Transfer solution to volumetric flask using a funnel and the stirring glass rod
- Transfer with washings of beaker rod and funnel to volumetric flask
- Funnel is removed, read at bottom of meniscus at eye level up to the mark
- Stopper flask and invert by 20
Washing of pipette
- Rinse pipette with deionised water
- Rinse pipette with solution it is gonna contain
- Use pipette filler
Filling up pipette
- Using a pipette filler, fill pipette with solution up to the mark at bottom of meniscus at eye level
- Do not mouth pipette
Transfering from pipette
- Transfer without blowing out the last drop
Washing burette:
- Rinse with deionised water
- Rinse with solution it is gonna contain
- Make sure to rinse the bit below the tap
Fill and use burette:
- Clamp vertically
- Using a funnel, fill the burette with the solution above the mark
- Remove funnel and adjust solution to the mark opening the tap. This wat the bit below the tap is also filled
- Read from bottom of meniscus at eye level
Ensure accuracy with burette:
- As you come near the end point of the titration, add the solution slowly, drop by drop
- Ensure burette is clamped vertically and read from bottom of meniscus at eye level
- Conical flask in white tile to be able to observe colour change
- Wash down walls, swirl and drop by drop
Exp. Use the standard solution of sodium carbonate to standardise HCl solution. INDICATOR:
Methyl orange
Yellow to pink
Exp. Vinegar
INDICATOR:
Phenolphthalein
Pink to colourless
