Inorganic Chemistry iGCSE Edexcel Double Chemistry

where are the alkali metals in the periodic table?

group 1

Name the first three elements in group 1

Lithium, Sodium, Potassium

What is the word equation for the reaction of an alkali metal with water?

metal + water --> metal hydroxide + hydrogen

Why are group 1 metals called alkali metals?

They form metal hydroxides, which are alkaline in solution

why do you see fizzing when sodium reacts with water?

Hydrogen is produced

what is the word equation for the reaction of an alkali metal with oxygen?

metal + oxygen --> metal oxide

What is the symbol equation for the formation of litium oxide?

4Li + O2 --> 2 Li2O

What happens when sodium reacts with oxygen?

It forms a mixture of sodium oxide (Na2O) and sodium peroxide (Na2O2)

What happens when potassium reacts with oxygen?

It forms a mixture of potassium peroxide (K2O2) and potassium superoxide (KO2)

What happens to the reactivity as you go down the alkali metals?

The reactivity increases as you go down the group--reacts more vigorously and more quickly

What are the first 4 halogens?

Fluorine, Chlorine, Bromine, Iodine

What is the pattern in physical properties going down the group?

As the atomic number increases, the colour gets darker and they have a higher boiling point

Describe the characteristics of chlorine

poisonous green gas

Describe the characteristics of bromine

poisonous red brown liquid that gives off an orange vapour

Describe the characteristics of iodine

dark grey crystalline solid which gives off a purple vapour when heated

What happens to the reactivity as you go down the halogens?

They get less reactive

What happens to the boiling point as you go down the group?

It increases

What is a displacement reaction?

When a more reactive element pushes out a less reactive one from a compound

What happens when you add chlorine water to potassium bromide solution?

Chlorine pushes the bromine out, turning the solution orange and forming potassium chloride

What happens when bromine water is mixed with potassium iodide solution?

Bromine pushes the iodine out, turning the solution brown and forming potassium bromide

What happens when bromine water is mixed with potassium chloride solution?

Nothing, as bromine is less reactive than chlorine and can't displace it.

Write the symbol equation for the reaction of chlorine water and potassium iodide solution

Cl2(aq) + 2KI(aq) --> I2(aq) + 2KCl(aq)

Show the redox reaction of chlorine water and potassium iodide solution

Cl2(aq) + 2I-(aq) --> 2Cl-(aq) + I2(aq)

In the reaction of chlorine water with potassium iodide solution, is the chlorine oxidised or reduced and why?

reduced, because it gains electrons

In the reaction of chlorine water with potassium iodide solution, is the iodine oxidised or reduced and why?

oxidised, because it loses electrons to the chlorine

What is an oxidising agent?

Something that accepts electrons and gets reduced

What is a reducing agent?

Something that donates electrons and gets oxidised

What are redox reactions?

Where reduction and oxidation happen at the same time

In the reaction of chlorine water with potassium iodide solution, is the chlorine an oxidising or reducing agent?

oxidising, because it gets reduced

In the reaction of chlorine water with potassium iodide solution, is the iodine an oxidising or reducing agent?

reducing, because it gets oxidised

How much of the atmosphere is nitrogen gas?

78%

How much of the atmosphere is oxygen gas?

21%

How much of the atmosphere is argon gas?

nearly 1%

How much of the atmosphere is carbon dioxide?

0.04%

Describe how you can find the proportion of oxygen in the atmosphere

1. soak some iron wool in acetic acid 2. put the iron wool in a measuring cylinder and invert it in a beaker of water 3. record the starting position of the water 4. leave it for a week and until the level stops changing 5. record the final position of water. 6. (start volume - final volume)/start volume tells you how much air was used up in the reaction to form rust. Should be about 20%

Describe how you can use phosphorus to find the percentage of oxygen in the air

1. put phosphorus in a tube with a glass syringe at either end, fill one with air and have the other empty.2. Heat the phosphorus and pass the air over the metal using the syringes to form phosphorus oxide. 3. The volume of air will decrease. 4. Push all the air into one of the syringes and calcuate the percentage decrease in the volume of air.

What is burning a reaction with?

oxygen in the air to form an oxide

What happens when magnesium is burned?

bright white flame, white power is magnesium oxide, which is slightly alkaline when dissolved in water

What is the symbol equation for burning magnesium?

2 Mg (s) + O2(g) --> 2MgO(s)

What happens when hydrogen is burned?

it burns easily, can be explosive, orange yellow flame, produces water vapour,in small amounts, the explosion gives a squeaky pop

What is the balanced symbol equation for burning hydrogen?

2H2(g) + O2(g) --> 2H2O(g)

What happens when sulfur is burned?

Produced a pale blue flame and produces sulfur dioxide, which is acidic when dissolved in water

What is the balanced symbol equation for burning sulfur?

S(s) + O2(g) --> SO2(g)

What does thermal decomposition mean?

breaking down a compound using heat

What happens when you heat a metal carbonate?

You get a metal oxide and carbon dioxide

What colour is copper(II)carbonate?

green

What colour is copper(II)oxide?

black

What is the balanced symbol equation for the thermal decomposition of copper carbonate?

CuCO3(s) --> CuO(s) + CO2(g)

What is the test for carbon dioxide?

turns limewater cloudy

How would you collect the CO2(g) from the thermal decomposition of Copper(II)carbonate?

It will sink to the bottom of a test tube from a delivery tube because it is denser than air

What is a greenhouse gas?

A gas in the atmosphere that acts as an insulating layer which absorbs the heat radiated from the Earth and reflect it back to the Earth

List three greenhouse gases

carbon dioxide, methane, water vapour (also CFC's, but this is from the biology spec)

What determines the temperature of the earth?

The heat energy it receives from the Sun and the heat energy it radiates back into space

What are the two main human activities that increase carbon dioxide in the atmosphere?

deforestation and burning fossil fuels

Why does deforestation increase levels of carbon dioxide?

fewer trees are available to take in carbon dioxide for photosynthesis

Why does burning fossil fuels increase the amount of carbon dioxide in the atmosphere?

carbon that was locked up millions of years ago is now being released

What has the increase in carbon dioxide done to the average temperature of the earth?

increased it

What is the heating up of the earth's atmosphere called?

global warming

What does global warming do to the climate?

it changes things such as rainfall, weather patterns, flooding, sea levels

What happens when metals react with acids?

They produce a salt and hydrogen gas

What is the word equation for the reaction of magnesium with hydrochloric acid?

magnesium + hydrochloric acid --> magnesium chloride and hydrogen

What is the word equation for the reaction of zinc with sulfuric acid?

zinc + sulfuric acid --> zinc sulfate + hydrogen

How would you measure the reactivity of metals in acid?

Measure the rate at which bubbles of hydrogen are given off

What is the test for hydrogen?

The squeaky pop test--put a lit splint to the mouth of the test tube and it makes a squeaky pop

What is the reaction of metals with water?

metal + water --> metal hydroxide + hydrogen

What is the word equation for the reaction of a less reactive metal with water?

metal +steam --> metal oxide + hydrogen

List three metals that will react vigorously with water

potassium, sodium, lithium, and calcium

List three metals that will react with steam

magnesium, zinc and iron

List three metals that will not react with water or steam

copper, silver, gold (as well as others)

What is the reactivity series?

It lists the metals in order of their reactivity

What is the most reactive metal?

Potassium

List the reactivity series in order from most to least

potassium, sodium, lithium, calcium, magnesium, aluminium, zinc, iron, copper, silver, gold

In the reaction of iron oxide and aluminium, does a reaction occur and what are the products?

yes, aluminium would displace the iron and form aluminium oxide and iron metal

In the reaction of iron oxide and aluminium, which reactant is oxidised and which is reduced?

Aluminium is oxidised and iron is reduced

In the reaction of copper sulfate and iron, does a reaction occur and what are the products?

yes, iron sulfate and copper are formed

In the reaction of copper sulfate and iron, which reactant is oxidised and which is reduced?

copper is reduced and iron is oxidised

In the reaction of silver metal and copper sulfate, does a reaction occur and what are the products?

No, because copper is more reactive than silver and it is already in the metal salt

Is the reaction of a metal and a metal salt exothermic or endothermic?

Exothermic

Why is iron useful?

it is used for building construction, car manufacture, and garden furniture

What is another name for corrosion of iron

rusting

What are the specific conditions needed for rusting?

iron exposed to oxygen and water

What are the reactions that occur when iron corrodes?

1. iron + oxygen --> iron (III) oxide and 2. water + iron(III) oxide --> hydrated iron (III) oxide

What is the word equation for rusting?

water + iron + oxygen --> hydrated iron (III) oxide

What are the two ways to prevent rusting?

1. barriers, either painting, coating with plastic, oiling or greasing or 2. sacrifical method, where a more reactive metal like zinc is placed with the iron, either as galvanising or by sticking pieces of zinc on the iron

How do we get pure metal?

It is extracted from a compound using reduction

What is oxidation?

reaction with/addition of oxygen or loss of electrons

What is reduction?

removal of oxygen or gaining of electrons

How do you test the pH of a solution?

use an indicator that changes colours

What is the pH of the strongest acid?

0

What is the pH of the strongest alkali?

14

What is the pH of pure water?

7

What is the pH of neutral?

7

What pH range is strongly acidic?

0-3

What colour is universal indicator in strongly acidic solutions?

red

What pH range is weakly acidic?

4 to 6

What pH range is weakly alkaline?

8 to 10

What pH range is strongly alkaline?

11 to 14

What colour is universal indicator in weakly acidic solutions?

orange or yellow

What colour is universal indicator in neutral solutions?

green

What colour is universal indicator in weakly alkaline solutions?

blue