acids and bases Flashcards
If the PH is below 7 Is is alkali or acid?
acid
if the PH is above 7 is it alkali or acid?
alkali
what is the ph of a neutral substance (eg pure water)
7
what is an indicator?
An indicator is a dye that changes colour depending on if its below or above a certain PH.
What is a wide range indicator?
A mixture of dyes that generally change colour over a broad PH (eg universal indicator).
What is a PH probe?
a device which can attach to a PH meter used to measure PH electronically.
How is a PH probe used?
It is placed in the solution you are measuring and the PH is given as a numerical value a digital screen.
Is a PH probe more or less accurate than an indicator?
more
What is an acid?
a substance that forms aqueous solutions with a PH below 7. ( acids form H+ ions in water)
what is a base?
A substance with a PH greater than 7
what is an alkali?
a base which dissolves in water to form a solution with a PH greater than 7 (alkali’s form OH- ions in water)
what is the neutralisation equation between acids and bases
acid+base=salt+water
or: H+ plus OH- =H2O
