Topic 3 Acids and Alkalis Flashcards
(36 cards)
Name some natural sources of indicators
red cabbage,
red rose petals,
beetroot,
red onion skin
What happens to red and blue litmus paper when placed in acid?
red paper remains red, blue litmus turns red
What happens to red and blue litmus paper when placed in alkali?
blue litmus remains blue, red litmus turns blue
What happens to red and blue litmus paper when placed in a neutral solution?
remain unchanged
Why is universal indicator better than litmus?
Litmus only tells if something is acid, alkali or neutral. Universal indicator indicates the strength of an acid or alkali.
What is pH and what should you remember?
pH is a measure of how acidic or alkaline a substance is. Remember it is small p capital H.
What pH do acids have?
Less than 7
What pH do neutral substance have?
7
What pH do alkalis have?
More than 7
What pH do strong acids have?
1-2 (low)
What pH do weak acids have?
3-6
What pH do neutral substances have?
7
What pH do weak alkalis have?
8-11
What pH do strong alkalis have?
12-14 (high)
What colour do strong acids turn universal indicator?
red
What colour do strong alkalis turn universal indicator?
purple
What colour do weak acids turn universal indicator?
orange at pH 3 to yellow at pH 6
What colour do weak alkalis turn universal indicator?
turquoise at pH 8 to blue at pH 11
What colour do neutral substances turn universal indicator?
green
Name some strong acids
stomach acid which is hydrochloric acid
Name some weak acids
lemon juice, vinegar, acid rain
Name a neutral substance
water
Name some weak alkalis
ammonia, toothpaste
Name some strong alkalis
oven cleaner, sodium hydroxide
