Chemistry unit 2 acids and alkalis Flashcards
What is a dye?
a substance that can change the colour of fabrics
Which indicators turn red in acid?
Beetroot, red onion and litmus
When using Universal indicator what colour is an acid?
reds and oranges
When using Universal indicator what colour is an alkali or base?
blues and purples
When using Universal indicator what colour is neutral?
Green
What PH is a strong acid?
0 - 4
What PH is a weak acid?
5 - 6
What PH is a strong alkali?
11 - 14
What PH is a weak alkali?
8 - 11
What PH is neutral?
7
Name an everyday acid you have at home
vinegar, lemon juice, apple juice
Name an everyday alkali you have at home
bleach, toothpaste, baking soda
name an everyday drink that is PH neutral
Water
Why does red cabbage make a good indicator?
Because the colour change is significant in acids and alkalis
How could you make indicator paper from red cabbage dye?
soaking paper in red cabbage and drying it
Name three safety precautions you should take when handling strong acids and alkalis?
gloves, goggles, lab coat, lidded containers
Name the equipment you would need to extract dye from a plant/leaf/berry
pestle and mortar, funnel, beaker,
What colour does acid go in red cabbage?
pink/red
What colour does alkali go in red cabbage?
Blue
What happens when you add water to a dye
It dilutes
Why is universal indicator so useful?
it changes colour at change in ph
What is the disadvantage of single colour change indicators?
Once they have changed colour, you can’t tell what the PH is
Why is it important to know what Ph soil is?
Certain crops like soil to be a particular ph
How do you test for the presence of hydrogen?
put a glowing splint in the test tube and see if it pops
