Obtaining & Using Metals Flashcards
All 23 cards in this deck
State the reactivity series in order from most to least reactive (including carbon and hydrogen).
Potassium, sodium, calcium, magnesium, aluminium, (carbon), zinc, iron, (hydrogen), copper, silver, gold.
Which of calcium, copper, silver and gold reacts with cold water?
Calcium. Copper, silver and gold do not react with cold water.
Why does copper produce no effervescence with dilute hydrochloric acid?
Copper is not reactive enough / low in the reactivity series (less reactive than hydrogen).
What does a metal's position in the reactivity series tell you about its atoms?
The higher up, the greater the tendency of its atoms to form cations (positive ions).
True or false? A metal high in the reactivity series resists oxidation better than a metal low in the series.
False. Metals low in the series (e.g. gold) resist oxidation best; reactive metals oxidise easily.
What are the steps to deduce an order of reactivity from reactions of metals with dilute acid?
e.g. silver: no change; iron: very slow bubbling; magnesium: steady bubbling
- Compare the rate/amount of effervescence: magnesium most, iron slow, silver none.
- More vigorous reaction = more reactive.
- List most to least reactive: magnesium, iron, silver.
When does a metal displace another metal from its salt solution?
When the added metal is more reactive than the metal in the salt.
e.g. zinc displaces copper from copper sulfate solution.Write the word equation for the reaction of magnesium with copper sulfate solution.
magnesium + copper sulfate → magnesium sulfate + copper
True or false? Copper displaces zinc from zinc sulfate solution.
False. Copper is less reactive than zinc, so no reaction occurs.
Which metal is usually found uncombined (native) in the Earth's crust: calcium, gold, iron or magnesium?
Gold. The others are too reactive and are found chemically combined.
In terms of oxygen, what are oxidation and reduction?
Oxidation is gain of oxygen; reduction is loss of oxygen.
In , which substance is oxidised and why?
Carbon — it gains oxygen to form carbon dioxide.
Why can iron be extracted by heating iron oxide with carbon?
Iron is less reactive than carbon, so carbon reduces the iron oxide.
Why is aluminium extracted by electrolysis rather than by heating its oxide with carbon?
Aluminium is high in reactivity (aluminium oxide is very stable), so aluminium oxide cannot be reduced by carbon.
Why is electrolysis not used to extract iron?
Electrolysis is expensive / needs a large amount of electricity; heating with carbon is cheaper.
Give two environmental advantages of recycling metals rather than extracting them from ores.
Less mining/quarrying, so habitats and landscapes are preserved; less waste goes to landfill.
Give an energy-related advantage of recycling aluminium rather than extracting it from its ore.
Less energy/electricity is required — it avoids the large amount of expensive electricity needed for electrolysis.
Give an advantage of recycling iron rather than extracting it from iron ore, in terms of carbon dioxide.
It avoids the carbon dioxide released when carbon burns; carbon dioxide is a greenhouse gas that causes global warming.
What four stages does a life-cycle assessment of a product consider?
Obtaining and processing the raw materials, manufacturing the product, using the product, and disposing of the product.
What does a life-cycle assessment measure about each stage?
The effect on the environment of that stage.
How does recycling metals help to preserve the supply of metal ores?
Metal ores are finite (non-renewable) and will eventually run out. Recycling means less ore has to be mined, so the supply lasts longer.
Give two economic advantages of recycling metals.
It is often cheaper than extracting new metal, because it uses less (costly) energy; and the recycling industry creates jobs.
How does iron react with cold water compared with steam?
It reacts only very slowly with cold water, but it does react with steam.