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Questions and Answers
What is a characteristic property of metals?
What is a characteristic property of metals?
Which state symbol represents a liquid in a balanced equation?
Which state symbol represents a liquid in a balanced equation?
How can rusting be prevented?
How can rusting be prevented?
What do metals form when they react with oxygen?
What do metals form when they react with oxygen?
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Which of the following is true about non-metals?
Which of the following is true about non-metals?
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What is the purpose of galvanizing iron?
What is the purpose of galvanizing iron?
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What does the term 'sacrificial protection' mean in the context of galvanizing?
What does the term 'sacrificial protection' mean in the context of galvanizing?
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How does the reactivity series classify metals?
How does the reactivity series classify metals?
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Which metals are most likely to be found in their elemental form in the Earth's crust?
Which metals are most likely to be found in their elemental form in the Earth's crust?
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Why is it more difficult to extract highly reactive metals from their ores?
Why is it more difficult to extract highly reactive metals from their ores?
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Study Notes
Reactions with Metals
- Metals react with oxygen to form metal oxides.
- Metal oxides are basic and form bases.
- Magnesium + oxygen → magnesium oxide is an example.
- Group 1 metals react rapidly with water, forming soluble hydroxides (alkalis) and hydrogen gas.
- Other metals are less reactive; transition metals react only with steam, not water.
Properties of Metals
- Good conductors of electricity.
- Good conductors of heat.
- Shiny (lustrous).
- High density (heavy for their size).
- Malleable (can be hammered into different shapes).
- Ductile (can be pulled into wires).
- Sonorous (make a ringing sound when hit).
Properties of Non-Metals
- Poor conductors of electricity (except graphite).
- Poor conductors of heat (except graphite).
- Dull.
- Low density (light for their size).
- Brittle (break when hammered or pulled).
- Not sonorous (make a dull sound when hit).
Writing Balanced Symbol Equations with State Symbols
- (s) means solid.
- (g) means gas.
- (l) means liquid.
- (aq) means aqueous solution.
- Example: 2Mg(s) + O2(g) → 2MgO(s)
- Example: NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)
Tests for Gases
| Gas | Test | Positive Observation | Balanced Equation |
|---|---|---|---|
| Hydrogen | Apply a lit splint to the gas | A 'squeaky pop' noise | 2H₂(g) + O₂(g) → 2H₂O(l) |
| Oxygen | Light a splint and blow it out; apply to gas | The splint will relight | Not applicable |
| Carbon Dioxide | Bubble the gas through limewater | A white precipitate of calcium carbonate forms (limewater goes cloudy) | Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) + 2H₂O(l) |
Rusting
- Chemicals in the air attack metals, causing the surface to be eaten away (corrosion).
- The corrosion of iron and steel is called rusting.
- For rusting to occur, both oxygen and water are needed.
- Rusting is sped up by electrolytes such as salt.
- Rust is weak, so it flakes away, exposing fresh metal to rust.
Stopping Rust
- Methods to prevent rusting include:
- Painting
- Coating with plastic.
- Greasing and oiling.
- Metal plating (e.g., chromium or tin).
- Galvanizing (coating with zinc).
Galvanizing
- Coating iron with zinc.
- Stops oxygen and water from reaching the iron.
- Zinc reacts with water, protecting the underlying iron (sacrificial protection).
The Reactivity Series
- A list of metals in order of their reactivity to water, oxygen, and hydrochloric acid.
- Reactivity (increasing): Potassium, Sodium, Calcium, Magnesium, Aluminium, Zinc, Iron, Tin, Lead, Hydrogen, Copper, Silver, Gold, Platinum .
- Elements below hydrogen do not react with cold water, steam, or hydrochloric acid.
- The more reactive a metal, the more difficult it is to extract from its ore and the more stable its compounds.
Metals at the Bottom of the Reactivity Series (Below Hydrogen)
- Unreactive (e.g., gold, silver, platinum).
- Exist as elements in the Earth's crust (native metals).
- Easily separated from other substances.
Metals in the Middle of the Reactivity Series (Between Hydrogen and Carbon)
- Exist as oxides.
- Carbon used to extract them (carbon reacts with the oxygen in the oxides forming carbon dioxide).
- Carbon is more reactive than the metals, so it displaces the metal from its compound.
Metals at the Top of the Reactivity Series (Above Carbon)
- Highly reactive (e.g., aluminum, sodium).
- Difficult to extract from their compounds.
- Extraction by electrolysis.
Metal Reactions with Water or Steam
- Metals exhibit varying reactivities with water or steam.
- Potassium and sodium react violently.
- Others, such as iron, react slowly.
- Copper & Silver do not react.
Comparing Metal Reactions with Acids and Oxygen
Tables provide relative reactions between various metals and dilute acid; compared with reactions with oxygen.
Displacement Reactions
- If metal X is more reactive than metal Y, it displaces Y in a compound.
- Example: Iron + copper sulphate → iron sulphate + copper.
Oxides in Displacement Reactions
- Some oxides can also be displaced by more reactive metals.
- Extracting metals from their ores involves displacing metals from their oxides.
- Aluminum + iron oxide → aluminum oxide + iron. (Thermite reaction)
- Example of displacement:Iron can displace copper from copper oxide.
Extracting Metals
- Most metals exist as compounds (in ores).
- Method of extraction depends on the metal's reactivity.
- The higher up a metal is in the reactivity series, the more difficult it is to extract.
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Description
This quiz covers the reactions of metals with oxygen and water, as well as the properties that distinguish metals from non-metals. Test your knowledge on writing balanced symbol equations and understand the basic characteristics of these elements. Perfect for students studying chemistry in secondary education.
