Chemistry Topic 4 - Chemical Changes Flashcards
How is the reactivity of metals vary on the periodic table?
Increase from top to bottom, and right to left
Most reactive and unreactive element?
Cesium is the most reactive though laboratories produced francium as most reactive
Platinum is the least reactive
What does reactivity mean?
Ability to produce positive ions. More reactive, easier it is to lose electrons to become positive
How to show how reactive a metal is
Reactive metals (Sodium or magnesium) will react violently with dilute acids, less reactive metals will react slowly
Reactive metals can react with cold water, less reactives one wont
The reactivity series
Potassium
Sodium
Lithium
Calcium
Magnesium
Carbon
Zinc
Iron
Hydrogen
Copper
How are metal oxides formed?
Reaction called oxidation as metals are gaining oxygen atoms
How do metals appear in the earths crust?
Compounds called ores
Often metal oxides
What must happen to metal oxides to become pure?
Get reduced and lost their oxygen atoms
How can reduction happen?
Reduction by electrolysis
Reduction by reaction with carbon
How to deduct whether a metal should be reduced by carbon or electrolysis?
If a metal is more reactive than carbon, they should be reduced with electrolysis, and less reactive than carbon should be used with carbon
Advantages of reduction by carbon?
Cheap
What is smelting and how is it a Example of reduction by carbon?
Iron (III) is heated to high temperatures (1200) and carbon is added to produce pure iron.
What happens if an element is so unreactive, they are unable to react with anything?
Are always found in their pure form
What type of reaction is extraction of oxygen from metals?
Redox reaction
Whats a redox reaction?
Involve transfer of electrons between reactants
What are acids?
Substances which produce H+ ions in aqueous solutions
What are bases?
Substances that produce OH- Ions in aquoeus solution
What are alkalis?
Bases which are soluble
Whats an alkaline?
A dissolved base
