acids, alkalis and indicators - SC8 Flashcards
how can acids and alkalis be measured?
on the pH scale
what pH describes a neutral property
pH 7
how would you describe a property with a lower pH than 7?
acidic
how would you describe a property with a higher pH than 7?
an alkali
what are acids in solution a source of?
hydrogen ions
what are alkalis in solution a source of?
hydroxide ions
how can the pH of a substance be found?
by indicators
If hydrogen ion concentration increases by 10, how much does the pH drop by
1
what does a high concentration of hydroxide ions indicate?
higher pH
what does a high concentration of hydrogen ions indicate?
lower pH
what does it mean when a solution is dilute?
the solution contains a small amount of dissolved solute
what does it mean when a solution is concentrated
the solutions has a large amount of dissolved solute
what does it mean when an acid is weak (in terms of dissociation into ions)
they only partly dissociate (will only lose/release one or 2 hydrogen ions)
what does it mean when an acid is strong (in terms of dissociation into ions)
they fully dissociate (break up, losing hydrogen)
name 4 common acids
hydrochloric acid, sulphuric acid, nitric acid, phosphoric acid
what is the pH of hydrochloric acid?
(HCl) pH 1
what is the pH of sulphuric acid
(H2SO4) pH 1.2
what is the pH of nitric acid
(HNO3) pH 1
what is the pH of phosphoric acid
(H3PO4) pH 1.4
what is true about all common acids?
they have hydrogen ions. this defines an acid
what salt does hydrochloric acid produce?
metal chloride
what salt does phosphoric acid produce
metal phosphate
what is a pH meter
a tool that accurately measures pH of different concentrations. The pH is how many H+ ions are in a solution
how many cm3 are in 1dm3
1000
what element makes an alkali?
OH-
