115307
Description
Flashcards by ashley.amber, updated more than 1 year ago
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Created by ashley.amber
over 12 years ago
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| Question | Answer |
| what is an indicator | a substance that indicates the presence of an acid or soluble base by turning different colours |
| what colour does blue litmus turn in a) an acid b)a neutral substance c)an alkaline | a)red b)purple c) blue |
| what colour does methyl orange turn in a)an acid b) a neutral substance c)an alkaline | a)orange b)yellow c)yellow |
| what colour does phenophaylein turn in an alkaline? | from colorless (in an acid and neutral) to pink |
| what does the pH scale measure? | acidity and alkalinity of a substance dissolved in water |
| what are the features of a neutral substance? | pH7 equal numbers of H+ and OH- ions |
| what are the features of an acid? | bellow pH7 higher concentration of H+ ions (than pure water) |
| what are the features of an alkali? | higher than pH7 higher concentration of OH- ions (than pure water) |
| what 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 |
| give 3 examples of a strong acid and give their formulas. | Hydrochloric- HCl Sulfuric- H2So4 Nitric- HNo3 |
| give an example of a weak acid | Ethanoic Citric |
| what does a base do? | neutralizes acids |
| what does a base do? | neutralizes acids |
| give 3 examples of a base and their formulas | sodium hydroxide- NaOH magnesium oxide- MgO ammonia- NH3 (most metal oxides/hydroxides are bases) |
| what 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. |
| what 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. |
| give 3 examples of common alkalis | sodium hydroxide- NaOH calcium hydroxide- (Ca(OH)2) Ammonia- (NH3) |
| metal+acid=? | salt+hydrogen |
| carbonate+acid=? | salt+carbon dioxde+ water |
| how is acidity in soil affected by acid rain? | It's neutralized by the calcium hydroxide in the rain (alkali) |
| acid+alkali=? | water molecules |
| is a neutralization reaction endothermic or exothermic? | exothermic (gives out heat) |
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