Paper 2- Inorganic Chemistry Flashcards
Explain the process of titration in detail. (using hydrochloric acid and sodium hydroxide as an example)
- Using pipette & pipette filler add some alkali (about 25cm3) to conical flask with 2/3 drops of indicator
- Fill a burette with acid & do this below eye level
- Using burette add acid to alkali a bit at a time & give conical flask a regular swirl
- Indicator changes colour when all alkali has been neutralised (e.g phenolphthalein = pink in alkalis but colourless in acids)
- record volume of acid used to neutralise alkali
- repeat process for reliable results
Titration calculation formula
mol
vol x conc
Give the steps taken in a titration calculation when you need to find the concentration of an acid
1) work out the moles of the known substance
Name the elements in the reactivity series
Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Copper Silver Gold
Name the 4 most reactive elements in the reactivity series
Potassium
Sodium
Lithium
Calcium
Name the 3 fairly reactive elements in the reactivity series
Magnesium
Aluminium
Zinc
Name the 3 not very reactive elements in the reactivity series
Iron
Copper
Silver
Name the not reactive element in the reactivity series
Gold
How does metals reacting with dilute acids tell you how reactive they are
-the more reactive the metal the faster the reaction will go
acid + metal –>
salt + hydrogen
Describe the steps you would take in the practical to investigate the differences in reactivity of a variety of metals by using their reaction with acids
1) set up 3 boiling tubes and fill with equal volumes of dilute hydrochloric acid/ dilute sulfuric acid
2) place pieces of magnesium, zinc, iron in separate test tubes
- speed of reaction is indicated by the rate of hydrogen bubbles given off
- hydrogen is confirmed by burning splint test
give the word equation for metals reacting with water
metal + water –>
metal hydroxide + hydrogen
how do very reactive metals react with water
- react vigorously with water:
- produce bubbles of hydrogen gas
how do less reactive metals react with water
-won’t react much with cold water
why do more reactive metals displace less reactive metals
- as more reactive metals react more strongly than less reactive metals
- meaning more reactive metals displace a less reactive metal from its oxide as it will bond more strongly to the oxygen
iron oxide + aluminium –>
-which element is being displaced in this reaction
aluminium oxide + iron
-iron would be displaced from iron oxide by the more reactive aluminium
what occurs if you put a reactive metal into a solution of a less reactive metal
-reactive metal replaces the less reactive metal in the salt
copper sulfate + iron –>
iron sulfate + copper
what happens if a piece of silver metal is put into copper sulfate solution
-nothing happens as the more reactive metal (copper) is already in the salt
What conditions are needed for iron to rust?
Oxygen and Water
What is the name of the chemical reaction that occurs when iron rusts
-oxidation reaction
What is the chemical name of rust?
Hydrated iron(III) oxide
How can barrier methods prevent rust
-barrier methods coat the iron with a barrier keeping out the water and oxygen
Name some barrier method to prevent rust
- paint
- oil
- grease
Name another way of preventing iron rusting other than barrier methods
-what does this method involve
- sacrificial method
- involved placing a more reactive metal (zinc) with the iron.
- The water and oxygen then react with the sacrifical metal instead of iron
Rusting can be prevented by spraying iron in zinc, this is called …
Galvanising
Meaning of Oxidation
- Gain of oxygen
- Lose of electrons
Meaning of Reduction
- Loss of oxygen
- Gain of electrons
Meaning of Redox reactions
Reduction and Oxidation reactions.
Oxidising agent
-substance that oxidises the metal
-and gets reduced:
Gains electrons
Loses oxygen
Reducing agent
-substance that reduces metal
- and gets oxidised
- Loses electrons
- Gains oxygen
magnesium + oxygen –> magnesium oxide
-what is being oxidised in this freaction
-magnesium is oxidised to magnesium oxide
