Acid, Bases and Salts Flashcards
What color is methyl orange in acidic, alkalis and neutral solutions?
Acid - Red
Alkali - Yellow
Neutral - Orange
What color is thymolphthalein in acidic, alkalis and neutral solutions?
Acid - Colorless
Alkali - Blue
Neutral - Colorless
What color is blue litmus paper acidic, neutral and alkali solutions?
Acid - Turns red
Alkali - Stays blue
Neutral - Stays blue
What color is red litmus paper acidic, neutral and alkali solutions?
Acid - Stays red
Alkali - Turns blue
Neutral - Stays red
Acid + Metal →
Salt + Hydrogen
Acid + Base →
Salt + Water
Acid + Metal Carbonate →
Salt + Water + Carbon Dioxide
Acid + Metal Oxide/Hydroxide →
Salt + Water
Why are metal oxides normally based rather than alkalis?
Metal oxides are normally insoluble.
Alkalis are soluble bases.
What do acids produce in an aqueous solution?
H+ ions
What do bases produce in an aqueous solution?
OH- ions
What is pH?
The concentration of H+ ions in 1litre of a solution
Define Acids
Are proton donors
Are chemical compound that produce H+ ion in aqueous solution
Define Bases
Are proton acceptors as they ionize/dissociates in aq. solutions producing OH- ions
Differentiate between Strong and Weak Acids and Bases
STRONG:
completely ionizes/dissociates in aq. solution
WEAK:
partially ionizes in aq. solution
How is the relative acidity and alkalinity of a solution quantified?
Using pH scale/ universal indicator
which pH values describe an acid, alkali and neutral solution?
Acid - pH less than 7
Neutral - pH = 7
Basic - pH greater than 7
What is an oxide?
A chemical compound formed when an element reacts with oxygen in the air
Types of Metallic Oxides
Describe Them
Basic Oxides:
generally formed when a metal reacts with oxygen (EG: CaO)
Amphoteric Oxides:
they can neutralise both acids and bases to form a salt and water. Have both basic and acidic properties (EG: Al2O3)
Types of NM Oxides
Describe Them
Acidic Oxides:
an oxide that either produces an acidic solution upon addition to water and is formed when NM reacts with O2 (EG: CO2)
Neutral Oxides:
oxides which do not exhibit acidic nor basic characteristics (EG: H2O)
An insoluble base reacts with an acid to form a soluble salt. How can the salt be removed from the solution?
1: Add excess base to the acid
2: Filter the mixture and saturate the solution
3: Let crystals form
4; Let the water evaporate, then filter, wash and dry the crystals (excess method)
What is PRECIPITATION?
Precipitation is how insoluble salts are prepared
Method:
Dissolve salts in water and mix together
Filter to remove precipitate from mixture
Wash the salt (precipitate) to remove traces of other soluble impurities/ solutions
Leave salt in oven to dry
What is TITRATION?
Titration is how soluble salts are prepared
Method:
Put a certain amount of alkali in a flask
Add few drops of indicator solution
Add the acid very slowly from the burette, stir until colorless
Find out how much acid you used and repeat the process to be more accurate
Heat the solution, forming a saturate solution and leave to crystalize
If you are given a salt, how to you identify the first part of the name?
first part of name e.g. magnesium → use a base containing magnesium e.g. magnesium hydroxide
Why is excess added?
To make sure all the acid has neutralized/reacted
If you are given a salt, how to you identify the last part of the name (acid)?
chloride - hydrochloric acid
nitrate - nitric acid
sulfate - sulfuric acid
