Booklet 3 Flashcards
What is needed for rusting?
Water and Oxygen
What is Rusting?
The corrosion of iron
What is a disadvantage of physical barriers?
Stops working if the surface becomes scratched or broken
What is galvanising?
Coating something in iron or zinc
What is physical barrier protection?
Stops rusting by coating something to keep out air and water
Name a disadvantage of sacrificial protection
Stops working when more reactive metal is used up
Corrosion is what?
The Formation of a compound on the surface of a metal
What metals are used for sacrificial metals?
Magnesium or Zinc
What is rust?
Hydrated iron oxide
Name some types of physical barriers
Paint,oil,grease,tin and other less reactive metals
What speeds up rusting?
Salts or acids
What metal is obtained from Bauxite?
Aluminium
What metal is obtained from haematite?
Iron
What metal is obtained from galena?
Lead
What metal is obtained from cinnabar?
Mercury
What metal is obtained from argentite?
Silver
What does REDOX stand for?
Reduction and Reduction reactions
What does potassium manganite decompose to produce?
Oxygen gas
What decomposes to form oxygen and water? And what experiment is it from?
Hydrogen Peroxide (H2O2), the Elephants toothpaste experiment
What is used in the elephants toothpaste experiment to speed up the reaction?
A catalyst
Why does the chemical reaction in elephants toothpaste cause the chemical to push out of the container?
The oxygen gas is produced,since the molecules are further apart than liquids so the same number of molecules takes up more space and the oxygen quickly pushes it out of the container
Combustion can be described as what?
A rapid, exothermic,oxidation reaction
Define distiallation
Evaporation then condensation
Define Decomposition
The breaking down of a molecule to form more than 1 product
What does Sacrificial Protection involve?
Attaching iron to a more reactive metal
What colour will UI turn if a solution is an acid,neutral,alkali?
Warm colour e.g red
Green (only)
Blue or purple
What do acidic solutions tend to be?
Non-metals
What do Alkalies tend to be?
Metal oxides
What happens to elements which are burned in oxygen?
The are said to be oxidised
What is the word equation for Rust?
Iron+oxygen+water -> hydrated iron oxide (rust)
What is the percentage of oxygen in air?
20%
In the experiment about how much air is used in rusting, how can you prove that the reaction is complete?
The water rises by 20% which is the amount of oxygen in air so it is reasonable to say rust has formed. (Oxygen has been used)
Is corrosion a quick reaction?
No, but a more reactive metal can quicken the reaction
Can rust form if only water or iron are present?
No the reaction requires both chemicals
What does corrosion form to protect it from further rust?
An oxide layer
What properties does rust have?
Brittle and weak, crumbles and breaks
How can reduction be described?
The loss of oxygen
In the reduction of copper oxide, what do you use or reduced the copper?
Carbon
What is the word equation for the reduction of copper oxide?
Copper oxide + carbon -> copper + carbon dioxide
If copper oxide has been reduced using Carbon, what has been oxidised?
Carbon
What does stoichiometric mean?
Relating to quantities of reactants in simple integral ratios, as prescribed by an equation or formula.
(Used in a thermit reaction p15)
Name a metal which does not react with dilute acid
Sodium
What alloy is used for bridges?
Steel, as it is strong
What metal burns very brightly?
Magnesium
What defines being easily beaten into shape?
Malleable
