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37 Cards in this Set
- Front
- Back
What colour does litmus paper turn? |
Acid - red Alkali - blue |
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What colour does phenolphthalein turn? |
Acid - colourless Alkali - pink |
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What colour does methyl orange turn? |
Acid - red Alkali - yellow |
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On the pH scale, what does each number mean? |
7 - neutral 1 - strong acid 6 - weak acid 8 - weak alkali 14 - strong alkali |
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Define an acid |
Acids are substances which dissociate in water and release hydrogen ions (h+) |
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Define an alkali |
Alkalis are substances which dissolve in water to release hyrdoxide ions (OH-) |
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What is the name for a reaction between an acid and alkali? |
Neutralization? |
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Equation for neutralization? |
H+ (aq) + OH- (aq) --> H20 (l) |
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What are the products of a metal and acid reaction? |
Salt + hydrogen |
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What are the products of a metal oxide and acid reaction? |
Salt + water |
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What are the products of a metal hydroxide and acid reaction? |
Salt + water |
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What are the products of a metal carbonate and acid reaction? |
Salt + water + carbon dioxide |
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What is hydrogen chloride? |
A halogen compound -- covalent compound which has a low melting and boiling point and does not conduct electricity. |
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What does hydrogen chloride do in water? |
When dissolved in water it dissociates to become hydrochloric acid. |
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What are the features of hydrochloric acid? |
Corrisive Low pH Reacts easily with metals, bases and metal carbonates |
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Equation for dissociation of hydrogen chloride? |
HCl (g) + H2O (l) --> H3O+ (aq) + Cl- (aq) |
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Simplified equation for dissociation of hydrogen chloride? |
HCl (aq) --> H+ (aq) + Cl- (aq) |
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What happens when hydrogen chloride is added to methylbenzene? |
The dissociation process does not occur and as a result hydrogen chloride does not behave like an acid (does not change colour of universal indication and does not conduct electricity) |
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Which salts are soluble? |
All nitrates All chlorides except silver and lead All sulphates except barium, lead and calcium Sodium and potassium carbonates All sodium, potassium and ammonium salts. |
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Which salts are insoluble? |
Silver chloride and lead chloride Barium, lead and calcium sulphate All carbonates except sodium and potassium |
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How do we make samples of pure dry crystals of a salt if the salt is not soluble? |
Precipitation or the process of obtaining dry salt from solution |
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What is the process of Precipitation? |
Make 2 solutions each one containing 1 ion of the salt to be madeAdd solutionFilter off precipitate which is the insolube saltWas the residue with distilled water to remove any of the salt solutionsDry with filter paper or on warm gauze |
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What is the process of obtaining dry salt from solution? |
Concentrate solution until it becomes saturated which is done by driving off most of the water by heating it. Solution is saturated when crystals form on a glass rod dipped in the solution. Stop heating and allow sollution to cool and salt crystals to form FIlter the crystals to remove water Wash crystals with distilled water to remove any remaining acid/alkali Dry crystals with filter paper or place on warm gauze. |
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How do we make samples of pure dry crystals of a salt if the salt is soluble with a soluble base? |
Titration: Add acid via burette to alkali + indicator until neutral (or until temperature stops rising) Measure volume of acid added : throw away solution as it contains the indicatior Add same volume of acid to same amount of alkali without inidcator Obtain dry salt from solution |
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How do we make samples of pure dry crystals of a salt if the salt is soluble with an insoluble base? |
Add excess base: Add excess base to acid until no more dissolves (warm if necessary) Filter off excess base Obtain salt solution. |
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How to carry out flame test?
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Nichrome wire in nitric acid and then burnt in flame until colourless. Clean again in acid and then dip into sample that needs to be tested. Sample held in flame with air inlet hole open. |
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Flame test results for: Li+ Ca2+ K+ Na+ Ba2+ Sr2+ Cu2+ |
Bright red Brick red Lilac Golden yellow Apple green/yellow Crimson Blue/green |
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Test for: Fe2+ Fe3+ Al3+ Cu2+ |
Add aqueous sodium hydroxide (NaOH) Green precipitate Brown precipitate White precipitate (dissolves in excess) Blue precipitate |
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Test for NH4 + |
Add aqueous sodium hydroxide (NaOH) and warm, test gas given off with damp red litmus paper (should turn blue) |
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Tests for: Cl- I- Br- |
Acidify with dilute nitric acid (HNO3) and add aqueous silver nitrate (AgNO3). White precipitate Yellow precipitate Cream precipitate |
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Test for CO3 2- |
Add HCl. Fizzing produces CO2 (test by bubbling gas through limewater - it turns cloudy) |
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Test for SO4 2- |
Acidify with hydrochloric acid (HCl) and add aqueous barium chloride (BaCl2). White precipitate |
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Test for hydrogen gas |
Lighted splint -squeaky pop |
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Test for oxygen gas |
Glowing splint - relights |
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Test for carbon dioxide gas |
Bubble through limewater - turns cloudy |
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Test for ammonia gas |
Damp red litmus paper - turns blue |
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Test for chlorine gas |
Damp red/blue litmus paper - bleaches |