acids, bases, and salts Flashcards
What is the formula between Acids with metal carbonates?
Acid + Metal Carbonate → Salt + Carbon Dioxide + Water
What is the formula between Acids with bases?
Acid + Base → Salt + Water (neutralization reaction)
What is the formula between Acids and metals?
Acid + Metal → Salt + Hydrogen
What is the formula between Alkalis and ammonium salts? (decomposition reaction)
For example, NH4Cl + NaOH →NaCl + H2O + NH3
What’s an acid?
A specie that dissociates in water to release H+ ions
What are the physical properties of acid?
- Sour taste
- Corrosive
- Turns blue litmus to red
- Strong acids are good electrolytes (conduct electricity)
How do you use the universal indicator differentiate between strong and weak acids? (process)
- Dip universal indicator in equal amount
of different acids - Compare the color with the pH chart
- If pH is low then it is a strong acid; vice versa
What is the meaning of the term ‘weak acid’?
It means that it partially dissociates in water
Methanesulfonic acid is a stronger acid than ethanoic acid.
Explain this statement
Methanesulfonic acid completely dissociates in water to release H+ ions whereas ethanoic acid partially dissociates in water
What’s an alkali?
a specie that dissociates in water to release OH- ions
What are the physical properties of bases?
- bitter taste
- feels soapy and slippery
- Turns red litmus to blue
- Strong alkalis are good electrolytes (can conduct electricity due to free ions)
How do you use the universal indicator to differentiate between strong and weak alkalis? (process)
- Dip the universal indicator in equal amounts of both alkali solutions
- Compare the color with the pH chart
- The greater the pH, the stronger the alkali
Which statement describes a weak acid?
It is a proton donor and is partially ionized in an aqueous solution
Define pH.
A measure of acidity or alkalinity of solutions
Aqueous ammonia reacts with a compound to form a salt, ammonium phosphate.
What type of reaction will ammonia undergo to form ammonium phosphate?
Neutralization
How can we find pH?
- Litmus solution ( test for acids and bases)
- it only tells us about acid or base and no pH
Methyl orange indicator.
COLOR in ACID:
COLOR in NEUTRAL:
COLOR in BASE:
COLOR in ACID: RED
COLOR in NEUTRAL: ORANGE
COLOR in BASE: YELLOW
Phenothalein indicator.
COLOR in ACID:
COLOR in NEUTRAL:
COLOR in BASE:
COLOR in ACID: Colorless
COLOR in NEUTRAL: Colorless
COLOR in BASE: Pink
Thymolphthalein indicator.
COLOR in ACID:
COLOR in NEUTRAL:
COLOR in BASE:
COLOR in ACID: Colorless
COLOR in NEUTRAL: Colorless
COLOR in BASE: Blue
Why do we use the universal indicator method to find pH on paper?
- It gives a rough idea of the pH
- Therefore, It’s better than using the litmus test method
Why is it not advisable to add fertilizers and limewater simultaneously? (2)
- Ammonium salts react with limewater to give off ammonia gas.
- As a result, nitrogen content for plants decreases since ammonia gas escapes to its surroundings.
What’s salts?
it is a specie formed when hydrogen of an acid is replaced by a metal.
Explain the process of titration.
- Take the measured amount of HCl and NaOH in a burette and conical flask.
- Pour a few drops of indicator into the conical flask
- Allow HCl to pour into the conical flask until a color change is observed.
- Note the volume of HCl used
- perform titration again using the noted volumes of HCL and NaOH
- {for evaporation} Boil off the solution 1/3rd and allow it to cool and crystallize.
- {for evaporation} Dry them between sheets of filter paper
Explain the process of crystallization.
- Put excess CuO in a beaker containing HCl
- Gently mix it until no more solid is disappearing
- Filter off the excess CuO
- {for evaporation} Boil off the solution 1/3rd and allow it to cool and crystallize.
- {for evaporation} Dry them between sheets of filter paper
Why is the excess CuO used?
To ensure that all the acid has reacted
Explain the process of insoluble salts.
PRECIPITATION: TWO SOLUBLE salts react to give an INSOLUBLE salt and SOLUBLE salt
- Put salt solution 1 into a beaker of salt solution 2
- Gently mix until no more solid is forming
- Perform filtration to obtain the insoluble salt formed
- Wash the salt crystals with distilled water and dry them between sheets of filter paper.
