Metals and Alloys

Flashcards about metals, alloys, corrosion and their reactions with water and acids, based on lecture notes.

List four physical properties of a typical metal.

Flexible, shiny, strong, can be stretched and hammered into shapes, good conductors of heat and electricity

What factors influence the decision to use one metal rather than another?

Cost, appearance, and its precise properties.

What speeds up a chemical reaction without being permanently changed itself?

Catalyst

What is a catalyst?

A catalyst is a substance that changes the speed of a reaction without being permanently changed itself.

Why are metal catalysts used in car exhaust systems?

To facilitate reactions that change dangerous gases into harmless ones.

Describe two uses of catalysts in everyday life.

In gas hair curlers to speed up the reaction that releases heat; in catalytic converters in cars to change dangerous gases into harmless ones.

What is corrosion?

Metal reacts with oxygen at the surface.

What is rusting?

Reaction with oxygen at the surface of iron.

Which element in the air reacts with tin?

Oxygen.

Give two reasons why the corrosion of titanium roofs is not a problem.

Strength of the metal is unaffected and protects it from further corrosion.

Word equation for the corrosion of titanium

Titanium + oxygen -> titanium oxide; symbol equation: Ti + O2 -> TiO2

What are the two other reactants needed for iron to rust?

Oxygen and water.

What elements are there in rust?

Iron, oxygen, and hydrogen.

Describe five barrier methods for preventing corrosion.

Painting, oil coating, plastic coating, powder coating, Galvanizing

What are the formulae for the products of the reaction between sodium and water?

NaOH (sodium hydroxide) and H2 (hydrogen)

What evidence indicates that a reaction is taking place between a metal and water?

Bubbles forming on the metal's surface.

Describe the test for hydrogen gas.

The gas burns with a squeaky pop.

Write the following metals in order of increasing reactivity: lithium, copper, tin, zinc.

Copper, tin, zinc, lithium

Name a metal that does not react with water or oxygen.

Platinum, gold, silver

Reacts with oxygen but not at all with water.

Copper

Where would you place metal X in the reactivity series?

Between lithium and calcium

Give the products formed when is metal X reacts with water?

Metal hydroxide and hydrogen

Explain how you can protect iron structures against acid rain.

Paint iron structures

Explain how you would test rainwater to see how acidic it was.

Use pH paper

Name the salt formed by the reaction between calcium and nitric acid

Calcium nitrate

Name the salt formed by the reaction between lithium and hydrochloric acid.

Lithium chloride

Name the products formed when acid rain, containing sulfuric acid, falls on an unprotected iron structure.

Iron sulfate and hydrogen

Zinc reacts with sulfuric acid (H₂SO₄) to form zinc sulfate (ZnSO₄). Write a word equation and a symbol equation for the reaction

Zinc + sulfuric acid -> zinc sulfate + hydrogen; Zn + H2SO4 -> ZnSO4 + H2

Zinc reacts with sulfuric acid (H₂SO₄) to form zinc sulfate (ZnSO₄). Describe how you could obtain a solid

Evaporate filtrate

Explain the difference between a mixture and a pure substance.

A mixture contains different substances which are not chemically bonded; a pure substance contains only one substance.

List the main properties of a typical metal.

Shiny, strong, malleable, conduct electricity, conduct heat.

What are mixtures of metals called?

Alloy

What is an alloy?

A mixture of metals.

Explain the difference in properties between this alloy and the metals it is made from in terms of the arrangement of atoms.

The presence of different atoms prevents layers sliding easily.

Which alloy has been made to be less reactive?

Stainless steel

What is solder used for?

For joining metals together.

Two old pieces of iron were tested. Iron X melted at exactly 1535 °C. Iron Y melted between 1400 °C and 1450 °C. Which sample was pure iron? Explain your answer.

Iron X; pure substances melt at precise temperatures.

Suggest why most are made

To reduce reactivity

What is rust and what causes it?

It is the corrosion of iron; corrosion of iron caused by oxygen and water.

What is an alloy?

A mixture of metals.

Why would tools made of bronze be better than tools made of copper?

They are harder and more durable.

How does coating the iron stop it from rusting?

Provides a barrier to oxygen and water.

Name the products of the reaction between zinc and sulfuric acid.

Zinc sulfate and hydrogen.