Reactivity Series Flashcards
Basics of the reactivity series
- Metals can be arranged based on how reactive they are, and this can be achieved by testing them against cold water, steam and dilute HCl
- Arranged from most reactive to the least reactive
Reactivity Series (Cations)
Potassium, Sodium, Calcium, Magnesium, Carbon, Zinc, Iron(II), Lead(II), Hydrogen, Copper, Silver, Gold
Reaction of the metals with cold water
- The more reactive you are, the bigger the reaction which means as you go down the reactivity series the reaction gets smaller
- Forms a metal hydroxide and hydrogen gas
- Exceptions are the moderately reactive elements and lead silver gold copper
Reaction of the metals with steam
- The more reactive you are, the bigger the reaction, meaning as you go down the reactivity series the reaction gets smaller
- Forms a metal oxide and hydrogen gas
- Exceptions are lead copper silver gold
Details pertaining specfically to the elements. (IMZ)
- Everything above Mg reacts explosively with steam
- Iron must be constantly heated in order for the reaction to progress
- For Mg, a white glow is produced when in contact w steam
- For Zn, zinc oxide is yellow but becomes white when it cools down
Reaction of the metals with HCl
- Always forms a metal chloride and hydrogen gas
- Can only react with elements that are above it in the reactivity series
- Does not react at all with lead copper silver gold
Reduction of Metal Oxides with Carbon
- Metal Oxide + Carbon -> Metal + CO2
- Acts as a reducing agent for metals below it in the reactivity series to extract the metal out of its oxide
- Zn requires the highest temperature for reduction (more reactive = more stable and stronger bonds between oxide, harder to break down)
Reduction of Metal Oxides for Hydrogen
- Metal Oxide + Hydrogen -> Metal + Steam, facilitated by heat
- Hydrogen only acts as a reducing agent for metals below iron to extract the metal out of its oxide
- iron requires the highest temperature to be reduced as is the most reactive
Ore
A large volume of earth and ground mixed w metal
Extracting metal from ore
- Method of extraction is determined by the position in the reactivity series
- Higher reactivity: Electrolysis as compounds are difficult to break down
- Lower reactivity: Reduced by carbon
What do more reactive metals have a tendency to do
Form cations compared to a less reactive metal, basically lose electrons, thus oxidised
Displacement
- A metal can reduce a metal lower in reactivity from its salt solution
- A metal can reduce a metal lower in reactivity from its oxide
- basically the more reactive metal displaces the less reactive metal
Effect of heat on metal carbonates
- The more reactive metal is harder to decompose by heat as it holds on to the carbonate very strongly
- Carbonates of K and Na don’t react w heat
- Carbonates below Na react with heat to form an oxide and CO2
- Silver Carbonate react with heat to form silver oxide, which is thermally unstable and further decomposes into silver, along w CO2
Conditions for rusting
- Water
- Oxygen
- NaCl which accelerates the rate of rusting
- When a metal is left in damp air, a reddish-brown solid forms over it
- Iron oxidises during rusting to form hydrated Iron(III)Oxide
- Rust is flaky and brittle
Preventing Rusting
Barrier Methods
1. Painting: If paint gets scratched, rusting may still happen
2. Oiling: Dust may gather and needs to be renewed constantly
3. Plastic Coating: Might get scratched and rusting may still happen
4. Tin-plating: Tin layer might get scratched and thus, rusting still will happen
5. Chrome-plating: Shiny layer and prevents rusting
Sacrificial Protection
- Using a more reactive metal to protect the iron since it will corrode in place of the iron
1. Galvanising/Zinc Plating: Even if the zinc layer is scratched, the iron won’t rust
2. Attaching zinc/Mg cubes: Corrodes in place of iron as they are more reactive
Qualitative Analysis
- metals in solid form are typically grey
- anything mixed with nitrate is colourless except for copper and iron
- when nitrate is mixed w copper the solution is blue
- when nitrate is mixed w iron(II) the solution is green
- copper is reddish-brown in solid form
