Flashcards
acids and bases
Flashcards do conjunto (22)
- 1what is an indicatora substance that indicates the presence of an acid or soluble base by turning different colours
- 2what colour does blue litmus turn in a) an acid b)a neutral substance c)an alkalinea)red
b)purple
c) blue - 3what colour does methyl orange turn in a)an acid b) a neutral substance c)an alkalinea)orange
b)yellow
c)yellow - 4what colour does phenophaylein turn in an alkaline?from colorless (in an acid and neutral) to pink
- 5what does the pH scale measure?acidity and alkalinity of a substance dissolved in water
- 6what are the features of a neutral substance?pH7
equal numbers of H+ and OH- ions - 7what are the features of an acid?bellow pH7
higher concentration of H+ ions (than pure water) - 8what are the features of an alkali?higher than pH7
higher concentration of OH- ions (than pure water) - 9what is the difference between a strong and weak acid?a strong acid has a higher concentration of H+ ions and a pH value between 0 and 3. a weak acid has a lower concentration of H+ ions and a pH value from between 3 and 6
- 10give 3 examples of a strong acid and give their formulas.Hydrochloric- HCl
Sulfuric- H2So4
Nitric- HNo3 - 11give an example of a weak acidEthanoic
Citric - 12what does a base do?neutralizes acids
- 13what does a base do?neutralizes acids
- 14give 3 examples of a base and their formulassodium hydroxide- NaOH
magnesium oxide- MgO
ammonia- NH3
(most metal oxides/hydroxides are bases) - 15what is an alkali?a soluable base which (when dissolved in water) is a source of OH- ions.
all alkalis are bases but not all bases are alkalis. - 16what is the difference between strong and weak alkalis?a strong alkali solution has a high concentration of hydroxide ions and a pH from between 11-14. a weak alkali has a lower concentration of OH- and a pH value from between 8-11.
- 17give 3 examples of common alkalissodium hydroxide- NaOH
calcium hydroxide- (Ca(OH)2)
Ammonia- (NH3) - 18metal+acid=?salt+hydrogen
- 19carbonate+acid=?salt+carbon dioxde+ water
- 20how is acidity in soil affected by acid rain?It's neutralized by the calcium hydroxide in the rain (alkali)
- 21acid+alkali=?water molecules
- 22is a neutralization reaction endothermic or exothermic?exothermic (gives out heat)
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- Cambridge IGCSE Biology FlashCards sobre acids and bases, criado por ashley.amber em 30-05-2013.
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