Podcast
Questions and Answers
Which of the following is NOT a primary method of preventing rust?
Which of the following is NOT a primary method of preventing rust?
- Sacrificial protection
- Applying a protective layer
- Using alloys
- Removing reactive metals (correct)
Why does iron rust more rapidly when a scratched tin layer exposes it, compared to normal rusting?
Why does iron rust more rapidly when a scratched tin layer exposes it, compared to normal rusting?
- Tin acts as a catalyst, speeding up the oxidation of iron.
- Iron is more reactive than tin, leading to accelerated corrosion. (correct)
- Tin donates electrons to the iron, increasing its reduction potential.
- The scratch creates a larger surface area for the iron to react with oxygen.
Which of the following best explains how grease prevents rusting on moving parts?
Which of the following best explains how grease prevents rusting on moving parts?
- Grease reacts with iron to create a passive layer, protecting the metal.
- Grease acts as a barrier, preventing water and oxygen from contacting the metal. (correct)
- Grease forms a conductive layer, preventing electron transfer during redox reactions.
- Grease neutralizes acids that catalyze the rusting process.
What role does aluminum oxide play in preventing further oxidation of aluminum?
What role does aluminum oxide play in preventing further oxidation of aluminum?
Why is rusting considered a nuisance?
Why is rusting considered a nuisance?
Which of the following is the primary chemical component of rust?
Which of the following is the primary chemical component of rust?
What two conditions are essential for rusting to occur?
What two conditions are essential for rusting to occur?
Why are metals like silver and gold used in electroplating?
Why are metals like silver and gold used in electroplating?
Which of the following describes galvanizing?
Which of the following describes galvanizing?
What is the purpose of using a drying agent in an experiment designed to investigate rusting?
What is the purpose of using a drying agent in an experiment designed to investigate rusting?
In the reactivity series, how does the stability of a metal's compound relate to the difficulty of extracting the metal?
In the reactivity series, how does the stability of a metal's compound relate to the difficulty of extracting the metal?
Which metals are typically extracted through electrolysis?
Which metals are typically extracted through electrolysis?
What is required to obtain pure unreactive metals such as gold?
What is required to obtain pure unreactive metals such as gold?
If Metal A displaces Metal B from its salt solution, what can be concluded?
If Metal A displaces Metal B from its salt solution, what can be concluded?
Which noble gas is commonly used to fill weather balloons, and why?
Which noble gas is commonly used to fill weather balloons, and why?
Flashcards
Rust prevention
Rust prevention
Removing reactants or providing sacrificial protection.
Protective layer
Protective layer
Using a protective layer like paint or grease.
Using alloys
Using alloys
Using alloys like stainless steel.
Painting
Painting
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Grease
Grease
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Plastic coating
Plastic coating
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What is rusting?
What is rusting?
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Chemical name of rust
Chemical name of rust
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Rusting requirements
Rusting requirements
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Reactivity series
Reactivity series
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Reactivity series
Reactivity series
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Properties of noble gases
Properties of noble gases
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Properties of noble gases
Properties of noble gases
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Study Notes
- Methods can prevent rusting by removing reactants and/or providing sacrificial protection
- Reactive metals form compounds in place of less reactive metals
Methods of Rust Prevention
- Using protective layers like painting, greasing, plastic coating, galvanizing, or electroplating
- Using alloys, such as stainless steel
Protective Layers
- Painting: Protects large iron and steel structures from oxygen and water
- Grease or Oil: Thin films protect moving parts from water and oxygen
- Plastic Coating: Protects iron and prevents water and oxygen contact
- Coating with Tin: Used on food cans, scratches lead to more rapid rusting of the iron underneath because iron is more reactive than tin
- Galvanizing: Coating an object with a protective layer of zinc metal
- Electroplating: Using precious, unreactive metals such as silver and gold on jewelry, rings, and coins
Stainless Steel
- Resistant to corrosion
- Used for cutlery and surgical instruments
Rusting Explained
- Rusting is the corrosion of iron
- Reddish-brown substance, rust, forms on the iron surface when exposed to oxygen and water over time
- Rust chemically is hydrated iron (III) oxide, which has the formula 4 Fe(s) + 3O2(g) + 2H2O(l) → 2Fe2O3.H2O(S)
- Rust flakes off, allowing underlying iron to rust leading to being a nuisance
- Aluminium also reacts with oxygen, forming aluminium oxide, a protective coat
Conditions for Rusting
- Both oxygen and water are needed for rusting to occur
Metal Extraction
- More reactive metals form more stable compounds increasing difficulty to extract
- Most metals exist as chlorides, oxides, carbonates, or sulfides in rocks
- An ore is a metal compound mixed with impurities
- The extraction method depends on the metal's position in the reactivity series
Reactivity Series
- Metals listed by reactivity to define extraction method
- Highly reactive metals are extracted by electrolysis of molten compounds
- Less reactive metals are extracted by carbon, carbon monoxide, or hydrogen reduction of oxides
- Unreactive metals are found uncombined
- Reactive metals need chemical extraction
- Unreactive metals require physical separation from impurities
Displacement
- A more reactive metal displaces a less reactive metal in a reaction
- The speed of reaction goes up the group
Reactivity Series
- Evidence the reactivity series comes from metal reactions with water and acids
Reaction of Metals
- React with oxygen form a oxide
- Form positive ions by losing electrons
- React usually with dilute acids to give an acid and salt
- Form ionic compounds like metal chlorides and oxides
Group 18 - Noble Gasses
- Noble gases are non-metal colorless gasses at room temperature
- Have low melting and boiling points
- Are insoluble
- Are inert and odourless
Noble Gasses Uses
- Helium is used for balloons
- Neon is used for making advertising lights
- Argon is used in light bulbs to prevent temperature oxidation
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