Acids And Bases Flashcards
0
Q
How does universal indicator work?
A
Dye changes colour depending on pH
Combination of dyes change colour gradually
Put drop of indicator onto substance and match on colour chart
1
Q
Describe ph scale
A
Scale from 0 (acid) to 7 (neutral) to 14 (alkalis)
Red, yellow, green, blue, purple
2
Q
Give examples of range of substances from 0 to 14 on pH scale
A
1 - very strong acid - stomach acid 3 - vinegar 5 - normal rain 7 - neutral - pure water 8 - washing up liquid 11 - soap powder 14 - very strong alkali - caustic soda (drain cleaner)
3
Q
What is an acid?
A
Substance with pH less than 7
Form H+ ions in water
4
Q
What is a base
A
Substance with pH greater than 7
Alkali is a base that is soluble in water
Alkalis form OH- ions in water
5
Q
What is neutralisation?
Give word equation
A
Reaction between acids and bases
Acid + Base = Salt + Water
H+ + OH-
6
Q
What pH do products have when they are neutralised?
A
pH 7
