C5 Flashcards
What are ores ?
Ores are naturally occurring rocks that contain metals or metal compounds in sufficient amounts to make it worthwhile extracting them .
In ores what is the main element that metals are chemically bonded to ?
Oxygen and often sulfur
What is an example of oxygen reacting with a metal in an ore ?
Iron + oxygen - iron oxide
To extract the metals from their oxides , what must happen ?
It must be reduced .
What are two ways you can compare the metal reactivity of each element ?
You can react them with either water or acid .
What is a dilute acid ?
Acid which contains greater concentrations of water in it
What is the reactivity series in order ?
Potassium
Sodium
Lithium
Calcium
Magnesium
Carbon
Zinc
Iron
Hydrogen
Copper
What gas is given off when metals react with water or dilute acids ?
Hydrogen
Is a displacement reaction another way to judge reactivity ? Explain why ?
Yes . This is because a more reactive metal will displace a less reactive metal from an aqueous solution of one of its salts .
Given an example of a displacement reaction .
In this case magnesium is more reactive than copper . Therefore the copper ions will displaced from solution to form copper metal . In this reaction , the magnesium metal forms aqueous magnesium ions and dissolves into the solution .
How does a displacement reaction work ?
Magnesium for example is placed into a solution like copper sulphate . Because magnesium is a more reactive element , it displaces copper from its solution
What does the reactivity series also show ?
How easily the metals want to form positive ions
Why are gases like carbon and hydrogen in the reactivity series ?
They are references to compare the metals against .
Where are metals found ?
In the earths crust
What does the term concentrating the ore mean ?
Getting rid of as much of the unwanted rocky material as possible .
What is oxidisation ?
When oxygen is added to an element or a compound .
What is reduction ?
Oxygen is removed from an element or compound .
Which metals in the reactivity series will react with water ?
Metals above hydrogen in the reactivity series .
When a metal reacts with water what are the products of the reaction ?
Metal hydroxide and hydrogen
What are the products of a metal reacting with an acid ?
Metal salt and hydrogen
Whether it is worth extracting a particular metal depends on three things . What are they ?
- How easily it is to extract the metal from a metal ore
- How much metal the ore contains
- The changing demands for a particular metal
As Gold and silver are so unreactive , what are they found as in the earth ?
They are found as metal elements themselves .
Is carbon also used to extract some metals from their ores ?
Yes
What is the process of carbon displacing another metal ?
You must heat the metal oxide with carbon . The carbon removes the oxygen from the metal oxide to form carbon dioxide .
What is an example of a metal oxide reacting with carbon ?
Lead oxide + carbon —-heat—- lead + carbon dioxide
What is chemical reduction ?
The removal of oxygen from its compound
When can reactions between metals and acids occur ?
When the metal is more reactive then hydrogen in the acid .
What is a salt ?
The general name for a compound formed when the hydrogen in an acid has wholly , or partially replaced metal ions .
What are the names of three strong acids ?
Hydrochloric acid , sulfuric acid and nitric acid .
What is a redox reaction ?
The reaction between a metal and an acid
What is a base ?
Something that reacts with an acid to neutralise and produce a salt .
Are bases soluble ?
No usually they are insoluble
What do insoluble bases names end with ?
Oxide
What is a soluble base and what name does it end with ?
Alkali metals and their name ends with hydroxide
What is another example of a base ?
Carbonate
What are the products formed when an acid reacts with a base ?
A salt and water are formed
What is the general equation that describes a neutralisation reaction ?
Acid + base — salt + water
What is a salt made up of ?
Made up of positive and negative ions from an acid .
What are the products formed when carbonate reacts with an acid ?
A salt , water and carbon dioxide gas.
What do the sum of charges on the ions in the salt add up to ?
Zero
When an acid reacts with an alkali is there a gas given off in the reaction ?
No
What are three examples of a weak acid ?
Citric acid , sulfuric acid and ethanoic acid
Is pure water acidic or alkaline ?
None of them , it is neutral
What ion does an acid release when added to water ?
H + ions
What produces OH - atoms when added to water ?
Alkali metals
What is ph a measure of ?
It is a measure of concentration of H+ ions in a solution
Is this statement true . Strong acids dissociate fully in water .
Yes
In weak acids do they ionise completley in a solution ?
No they stay the same . They do not release H+ ions
