Ch - 11 (Acids and Bases) Flashcards
What happens when acids are added to water?
Form positively charged hydrogen ions. (H+)
What makes a solution acidic?
Presence of H+ ions.
Give a word equation of acids reacting with metals?
Acid + Metal –> Salt + Hydrogen
Which metals in the reactivity series will react with dilute acids?
Metals above hydrogen
What can act as bases?
- Metal oxides
- Hydroxides (alkalis)
Give a word equation of acid reacting with base.
Acid + base –> Salt + water
Give an equation of the acid reacting with a metal carbonate.
Acid+ metal –> salt + carbon dioxide + water
What is one common indicator?
Litmus extracted from lichens
What are synthetic indicators?
Organic compounds that are sensitive to changes in acidity and appear different colours in acids and alkalis.
What are 2 synthetic indicators frequently used in acid - alkali titrations?
Thymolphthalein and methyl orange
What are synthetic indicators used for?
To show the endpoint in titrations as they have a very sharp change of colour when an acid has been neutralised by an alkali or vice versa.
Is litmus suitable for tritration? why or why not?
colour change is not so sharp, colour in neutral solution makes it difficult
What pH does a base have?
Above 7
What is a base?
water soluble referred to as an alkali
In basic (alkaline) what colour do the following change into:
- red litmus paper
- methyl orange
-thymolphthalein
- red litmus paper: blue
- methyl orange: yellow
-thymolphthalein: blue
What form are bases of metals?
Oxides or hydroxides
What happens when alkalis are added to water?
Form negative (OH-) ions
What makes a solution an alkali?
Presence of OH- ions