11/04/23

AQA Chemistry 2AQA Chemistry 2

A slideshow that covers the entire AQA 2006 Syllabus Chemistry 2 Module

W Richards

11/04/23

The structure of the atomThe structure of the atom

ELECTRON – negative,

mass nearly nothingPROTON –

positive, same mass as neutron

(“1”)

NEUTRON – neutral,

same mass as proton

(“1”)

The Ancient Greeks used to believe that everything was made up of very small

particles. I did some experiments in 1808 that proved this and called these particles

ATOMS:

Dalton

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Mass and atomic numberMass and atomic number

Particle Relative Mass Relative Charge

Proton 1 +1

Neutron 1 0

Electron Very small -1

MASS NUMBER = number of protons + number of neutrons

SYMBOL

PROTON NUMBER = number of protons (obviously)

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Mass and atomic numberMass and atomic numberHow many protons, neutrons and electrons?

11/04/23IsotopesIsotopesAn isotope is an atom with a different number of neutrons:

Each isotope has 8 protons – if it didn’t then it just wouldn’t be oxygen any more.

Notice that the mass number is different. How many neutrons does each isotope have?

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Electron structureElectron structureConsider an atom of Potassium:

Potassium has 19 electrons. These electrons occupy specific energy levels “shells”…

Nucleus

The inner shell has __ electrons

The next shell has __ electrons

The next shell has __ electrons

The next shell has the remaining __ electron

Electron structure

= 2,8,8,1

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Periodic Table IntroductionPeriodic Table Introduction

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Mendeleev

Periodic tablePeriodic table

The periodic table arranges all the elements in groups according to their properties.

Horizontal rows are called PERIODS

Vertical columns are called GROUPS

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H He

Li Be B C N O F Ne

NaMg

Al Si P S Cl Ar

K Ca Fe Ni Cu Zn Br Kr

Ag I Xe

Pt Au Hg

The Periodic TableThe Periodic TableFact 1: Elements in the same group have the same number of electrons in the outer

shell (this corresponds to their group number)

E.g. all group 1 metals have __ electron in their outer shell

These elements have __ electrons in their outer shell

These elements have __ electrons in their outer shells

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H He

Li Be B C N O F Ne

NaMg

Al Si P S Cl Ar

K Ca Fe Ni Cu Zn Br Kr

Ag I Xe

Pt Au Hg

The Periodic TableThe Periodic TableFact 2: As you move down through the periods an extra electron shell is added:

E.g. Lithium has 3 electron in the configuration 2,1

Potassium has 19 electrons in the configuration __,__,__,__

Sodium has 11 electrons in the configuration 2,8,1

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H He

Li Be B C N O F Ne

NaMg

Al Si P S Cl Ar

K Ca Fe Ni Cu Zn Br Kr

Ag I Xe

Pt Au Hg

The Periodic TableThe Periodic TableFact 3: Most of the elements are metals:

These elements are metals

This line divides metals from non-metals

These elements are non-metals

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H He

Li Be B C N O F Ne

NaMg

Al Si P S Cl Ar

K Ca Fe Ni Cu Zn Br Kr

Ag I Xe

Pt Au Hg

The Periodic TableThe Periodic TableFact 4: (Most important) All of the

elements in the same group have similar PROPERTIES. This is how I thought of the

periodic table in the first place. This is called PERIODICITY.

E.g. consider the group 1 metals. They all:

1) Are soft

2) Can be easily cut with a knife

3) React with water

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CompoundsCompounds

Compounds are formed when two or more elements are chemically combined. Some examples:

Glucose

Methane

Sodium chloride (salt)

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Some simple compounds…Some simple compounds…

Methane, CH4 Water, H2O

Carbon dioxide, CO2

Ethyne, C2H2Sulphuric

acid, H2SO4

Key

Hydrogen

Oxygen

Carbon

Sulphur

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Balancing equationsBalancing equationsConsider the following reaction:

Na

O

H HH H

Na

OH

Sodium + water sodium hydroxide + hydrogen

+ +

This equation doesn’t balance – there are 2 hydrogen atoms on the left hand side (the “reactants” and 3 on the right hand side (the “products”)

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Balancing equationsBalancing equationsWe need to balance the equation:

Na

O

H H

H H

Na

OH

Sodium + water sodium hydroxide + hydrogen

+ +

Na

O

H HNa

OH

Now the equation is balanced, and we can write it as:

2Na(s) + 2H2O(l) 2NaOH(aq) + H2(g)

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Some examplesSome examples

Mg + O2

Zn + HCl

Fe + Cl2

NaOH + HCl

CH4 + O2

Ca + H2O

NaOH + H2SO4

CH3OH + O2

MgO

ZnCl2 + H2

FeCl3

NaCl + H2O

CO2 + H2O

Ca(OH)2 + H2

Na2SO4 + H2O

CO2 + H2O

2

2

2 3

2

2

2

2 3

2

2

2

2

2 4

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BondingBonding

Hi. My name’s Johnny Chlorine. I’m in Group 7, so I have 7 electrons in my outer

shell

I’d quite like to have a full outer shell. To do this I need to GAIN an electron. Who can

help me?

Cl

Cl

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BondingBondingHere comes one of my friends,

Harry Hydrogen

Hey Johnny. I’ve only got one electron but it’s really close to my nucleus so I don’t want to

lose it. Fancy sharing?

Cl

H

Cl

H

Now we’re both really stable. We’ve formed a covalent bond.

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BondingBondingHere comes another friend,

Sophie Sodium

Hey Johnny. I’m in Group 1 so I have one electron in my outer

shell. Unlike Harry, this electron is far away from the nucleus so I’m

quite happy to get rid of it. Do you want it?

Cl

Now we’ve both got full outer shells and we’ve both gained a charge. We’ve formed an IONIC

bond.

Na

Okay

Cl

Na

+-

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Covalent bondingCovalent bondingConsider an atom of hydrogen:

Notice that hydrogen has just __ electron in its outer shell. A full (inner) shell would have __ electrons, so two hydrogen atoms get together and “_____” their electrons:

Now they both have a ____ outer shell and are more _____. The formula for this molecule is H2.

When two or more atoms bond by sharing electrons we call it ____________ BONDING. This type of bonding normally occurs between _______ atoms. It causes the atoms in a molecule to be held together very strongly but there are ____ forces between individual molecules. This is why covalently-bonded molecules have low melting and boiling points (i.e. they are usually ____ or ______).

Words – gas, covalent, non-metal, 1, 2, liquid, share, full, weak, stable

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Dot and Cross DiagramsDot and Cross Diagrams

HOH

Water, H2O:

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Dot and Cross DiagramsDot and Cross Diagrams

Oxygen, O2:

O O

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Dot and cross diagramsDot and cross diagramsWater, H2O:

Oxygen, O2:

OH H

O O

H

H

O

O O

Step 1: Draw the atoms with their outer shell:

Step 2: Put the atoms together and check they all have a full outer shell:

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Dot and cross diagramsDot and cross diagramsNitrogen, N2:

Carbon dioxide, CO2:Ammonia NH3:

Methane CH4:

H HN

H

HH

H

H

CN N

O OC

11/04/23Other ways of drawing covalent Other ways of drawing covalent bondsbonds

Consider ammonia (NH3):

H HN

HH HN

HH HN

H

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IonsIonsAn ion is formed when an atom gains or loses electrons and becomes charged:

If we “take away” the electron we’re left with just a positive charge:

This is called an ion (in this case, a positive hydrogen ion)

+-

+

The electron is negatively charged

The proton is positively charged

+

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Ionic bondingIonic bonding

Na

Na

+

This is where a metal bonds with a non-metal (usually). Instead of sharing the electrons one of the atoms “_____” one or more electrons to the other. For example, consider sodium and chlorine:

Sodium has 1 electron on its outer shell and chlorine has 7, so if sodium gives its electron to chlorine they both have a ___ outer shell and are ______.

A _______ charged sodium ion

A _________ charged chloride ion

As opposed to covalent bonds, ionic bonds form strong forces of attraction between different ions due to their opposite ______, causing GIANT IONIC STRUCTURES to form (e.g sodium chloride) with ______ melting and boiling points:

Cl

Cl

-

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Some examplesSome examples

Mg

Magnesium chloride:

MgCl2

Cl

Cl

+ Mg

2+

Cl

-

Cl

-

Calcium oxide:

CaO

OCa + Ca

2+

O

2-

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Giant structures (Giant structures (““latticeslattices””))

+

+

+

+

+++

+

+

1. Diamond – a giant covalent structure with a very ____ melting point due to ______ bonds between carbon atoms

2. Graphite – carbon atoms arranged in a layered structure, with free _______ in between each layer enabling carbon to conduct _________

3. Sodium chloride – a giant ionic lattice with _____ melting and boiling points due to ______ forces of attraction. Can conduct electricity when _______.

4. Metals – the __________ in metals are free to move around (“delocalised”), holding the _____ together and enabling it to conduct _________

11/04/23

A closer look at metalsA closer look at metals

+

+

+

+

+++

+

+Metals are defined as elements that readily lose electrons to form positive ions. There are a number of ways of drawing them:

+-

+-

+-

+- + - +-

+-

+-

+ + +

+ + +

+ +

Delocalised electrons

11/04/23

NanoscienceNanoscience

Nanoscience is a new branch of science that refers to structures built from a few hundred atoms and are 1-100nm big. They show different properties to the same materials in bulk. They also have a large surface area to volume ratio and their properties could lead to new developments in computers, building materials etc.

Definition:

Task: research nanoscience and find two current and/or future applications of this science.

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Group 1 – The alkali metalsGroup 1 – The alkali metals

Li

Na

K

Rb

Cs

Fr

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Group 1 – The alkali metalsGroup 1 – The alkali metals

1) These metals all have ___ electron in their outer shell.

Some facts…

2) Reactivity increases as you go _______ the group. This is because the electrons are further away from the _______ every time a _____ is added, so they are given up more easily.

3) They all react with water to form an alkali (hence their name) and __________, e.g:

Words – down, one, shell, hydrogen, nucleus, decreases

Potassium + water potassium hydroxide + hydrogen

2K(s) + 2H2O(l) 2KOH(aq) + H2(g)

2) Density increases as you go down the group, while melting point ________

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Group 0 – The Noble gasesGroup 0 – The Noble gases

He

Ne

Ar

Kr

Xe

Rn

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Group 0 – The Noble gasesGroup 0 – The Noble gasesSome facts…

1) All of the noble gases have a full outer shell, so they are very ______2) They all have _____ melting and boiling points

3) They exist as single atoms rather then _________ molecules

4) Helium is ________ then air and is used in balloons and airships (as well as for talking in a silly voice)

5) Argon is used in light bulbs (because it is so unreactive) and argon , krypton and ____ are used in fancy lights

Words – neon, stable, low, diatomic, lighter

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Group 7 – The halogensGroup 7 – The halogens

F

Cl

Br

I

At

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Group 7 – The HalogensGroup 7 – The HalogensSome facts…

1) Reactivity DECREASES as you go down the group

Decre

asin

greactiv

ity

(This is because the electrons are further away from the nucleus and so any extra electrons aren’t attracted as much).

2) They exist as diatomic molecules (so that they both have a full outer shell):

Cl Cl

3) Because of this fluorine and chlorine are liquid at room temperature and bromine is a gas

11/04/23The halogens – some The halogens – some reactionsreactions

1) Halogen + metal:

Na

+

Cl

-

Na Cl+

2) Halogen + non-metal:

H Cl+ Cl H

Halogen + metal ionic salt

Halogen + non-metal covalent molecule

11/04/23Atomic massAtomic mass

SYMBOL

PROTON NUMBER = number of protons (obviously)

RELATIVE ATOMIC MASS, Ar

(“Mass number”) = number of protons + number of neutrons

11/04/23Relative formula mass, MRelative formula mass, Mrr

The relative formula mass of a compound is the relative atomic masses of all the elements in the compound added together.

E.g. water H2O:

Therefore Mr for water = 16 + (2x1) = 18

Work out Mr for the following compounds:

1) HCl

2) NaOH

3) MgCl2

4) H2SO4

5) K2CO3

H=1, Cl=35 so Mr = 36

Na=23, O=16, H=1 so Mr = 40

Mg=24, Cl=35 so Mr = 24+(2x35) = 94

H=1, S=32, O=16 so Mr = (2x1)+32+(4x16) = 98

K=39, C=12, O=16 so Mr = (2x39)+12+(3x16) = 138

Relative atomic mass of O = 16

Relative atomic mass of H = 1

11/04/23

A “Mole”A “Mole”Definition:

A mole of a substance is the relative formula mass of that substance in grams

For example, 12g of carbon would be 1 mole of carbon...

...and 44g of carbon dioxide (CO2) would be 1 mole etc...

11/04/23Calculating percentage Calculating percentage massmass

If you can work out Mr then this bit is easy…

Calculate the percentage mass of magnesium in magnesium oxide, MgO:

Ar for magnesium = 24 Ar for oxygen = 16

Mr for magnesium oxide = 24 + 16 = 40

Therefore percentage mass = 24/40 x 100% = 60%

Percentage mass (%) =

Mass of element Ar

Relative formula mass Mr

x100%

Calculate the percentage mass of the following:

1) Hydrogen in hydrochloric acid, HCl

2) Potassium in potassium chloride, KCl

3) Calcium in calcium chloride, CaCl2

4) Oxygen in water, H2O

11/04/23

Recap questionsRecap questionsWork out the relative formula mass of:

1) Carbon dioxide CO2

2) Calcium oxide CaO

3) Methane CH4

Work out the percentage mass of:

1) Carbon in carbon dioxide CO2

2) Calcium in calcium oxide CaO

3) Hydrogen in methane CH4

11/04/23Calculating the mass of a Calculating the mass of a productproduct

E.g. what mass of magnesium oxide is produced when 60g of magnesium is burned in air?

Step 1: READ the equation:

2Mg + O2 2MgO

IGNORE the oxygen in step 2 – the question

doesn’t ask for it

Step 3: LEARN and APPLY the following 3 points:

1) 48g of Mg makes 80g of MgO

2) 1g of Mg makes 80/48 = 1.66g of MgO

3) 60g of Mg makes 1.66 x 60 = 100g of MgO

Step 2: WORK OUT the relative formula masses (Mr):

2Mg = 2 x 24 = 48 2MgO = 2 x (24+16) = 80

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Work out Mr: 2H2O = 2 x ((2x1)+16) = 36 2H2 = 2x2 = 4

1. 36g of water produces 4g of hydrogen

2. So 1g of water produces 4/36 = 0.11g of hydrogen

3. 6g of water will produce (4/36) x 6 = 0.66g of hydrogen

Mr: 2Ca = 2x40 = 80 2CaO = 2 x (40+16) = 112

80g produces 112g so 10g produces (112/80) x 10 = 14g of CaO

Mr: 2Al2O3 = 2x((2x27)+(3x16)) = 204 4Al = 4x27 = 108

204g produces 108g so 100g produces (108/204) x 100 = 52.9g of Al2O3

1) When water is electrolysed it breaks down into hydrogen and oxygen:

2H2O 2H2 + O2

What mass of hydrogen is produced by the electrolysis of 6g of water?

3) What mass of aluminium is produced from 100g of aluminium oxide?

2Al2O3 4Al + 3O2

2) What mass of calcium oxide is produced when 10g of calcium burns?

2Ca + O2 2CaO

11/04/23Another methodAnother methodTry using this equation:

Mass of product IN GRAMMES

Mass of reactant IN GRAMMES

Mr of product

Mr of reactant

Q. When water is electrolysed it breaks down into hydrogen and oxygen:

2H2O 2H2 + O2

What mass of hydrogen is produced by the electrolysis of 6g of water?Mass of product IN GRAMMES

6g

4

36

So mass of product = (4/36) x 6g = 0.66g of hydrogen

11/04/23Problems with this Problems with this techniquetechnique

Calculating the amount of a product may not always give you a reliable answer...

1) The reaction may not have completely _______

2) The reaction may have been _______

3) Some of the product may have been ____

4) Some of the reactants may have produced other _______

The amount of product that is made is called the “____”. This number can be compared to the maximum theoretical amount as a percentage, called the “percentage yield”.

Words – lost, yield, finished, reversible, products

11/04/23

Atom EconomyAtom Economy

Percentage atom economy =

Relative formula mass of useful product

Total masses of products

Calculate the atom economies of the following:

1) Converting ethanol into ethene (ethene is the useful bit):

C2H5OH C2H4 + H20

2) Making zinc chloride from zinc and hydrochloric acid:

Zn + 2HCl ZnCl2 + H2

11/04/23

Numbers of molesNumbers of molesConsider two liquids:

Now consider two gases:

20cm3 of 0.1mol/dm3 of hydrochloric acid

20cm3 of 0.1mol/dm3 of sodium hydroxide

These two beakers contain the same number of moles

20cm3 of helium at room temperature and pressure

20cm3 of argon at room temperature and pressure

These two gases contain the same number of moles

11/04/23Endothermic and exothermic Endothermic and exothermic reactionsreactions

Step 1: Energy must be SUPPLIED to break bonds:

Step 2: Energy is RELEASED when new bonds are made:

A reaction is EXOTHERMIC if more energy is RELEASED then SUPPLIED. If more energy is SUPPLIED then is

RELEASED then the reaction is ENDOTHERMIC

Energy

Energy

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Example reactionsExample reactionsReaction Temp. after

mixing/OCExothermic or endothermic?

Sodium hydroxide + dilute hydrochloric acid

Sodium hydrogencarbonate + citric acid

Copper sulphate + magnesium powder

Sulphuric acid + magnesium ribbon

11/04/23

Reversible ReactionsReversible ReactionsSome chemical reactions are reversible. In other words, they can go in either direction:

A + B C + D

NH4Cl NH3 + HCl

e.g. Ammonium chloride

Ammonia + hydrogen chloride

If a reaction is EXOTHERMIC in one direction what must it be in the opposite direction?

For example, consider copper sulphate:

Hydrated copper sulphate (blue)

Anhydrous copper sulphate (white)

+ Heat

+ Water

CuSO4 + H2OCuSO4.5H2O

11/04/23

Reversible ReactionsReversible ReactionsWhen a reversible reaction occurs in a CLOSED SYSTEM (i.e. no reactants are added or taken away) an EQUILIBRIUM is achieved – in other words, the reaction goes at the same rate in both directions:

A + B C + D

Endothermic reactions

Increased temperature:

Decreased temperature:

A + B C + D

A + B C + D

More products

Less products

Exothermic reactions

Increased temperature:

Decreased temperature:

A + B C + D

Less products

More products

A + B C + D

11/04/23

Making AmmoniaMaking Ammonia

Nitrogen + hydrogen Ammonia N2 + 3H2 2NH3

•High pressure

•450O C

•Iron catalystRecycled H2 and N2

Nitrogen

Hydrogen

Mixture of NH3, H2 and N2. This is cooled causing NH3 to liquefy.

Fritz Haber, 1868-1934

Guten Tag. My name is Fritz Haber and I won the Nobel Prize for chemistry. I am going to tell you

how to use a reversible reaction to produce ammonia, a very important chemical. This is called

the Haber Process.

To produce ammonia from nitrogen and hydrogen you have to use three conditions:

11/04/23Haber Process: The Haber Process: The economicseconomicsA while ago we looked at reversible reactions:

A + B C + D

Endothermic, increased temperature

A + B C + D

Exothermic, increase temperature

ExothermicEndothermic

1) If temperature was DECREASED the amount of ammonia formed would __________...

2) However, if temperature was INCREASED the rate of reaction in both directions would ________ causing the ammonia to form faster

3) If pressure was INCREASED the amount of ammonia formed would INCREASE because there are less molecules on the right hand side of the equation

Nitrogen + hydrogen Ammonia

N2 + 3H2 2NH3

11/04/23

Haber Process SummaryHaber Process Summary

•200 atm pressure

•450O C

•Iron catalyst

Recycled H2 and N2

Nitrogen

Hydrogen

Mixture of NH3, H2 and N2. This is cooled causing NH3 to liquefy.

To compromise all of these factors, these conditions are used:

A low temperature increases the yield of ammonia but is too slow

A high temperature improves the rate of reaction but decreases the yield too much

A high pressure increases the yield of ammonia but costs a lot of money

11/04/23

Rates of ReactionRates of Reaction

Hi. I’m Mike Marble. I’m about to have some acid poured onto me. Let’s see what happens…

Here comes an acid particle…

It missed!

Here comes another one. Look

at how slow it’s going…

No effect! It didn’t have enough

energy!

Oh no! Here comes another one and it’s got more energy…

11/04/23

Rates of ReactionRates of ReactionChemical reactions occur when different atoms or molecules _____ with enough energy (the “________ Energy):

Basically, the more collisions we get the _______ the reaction goes. The rate at which the reaction happens depends on four things:

1) The _______ of the reactants,

2) Their concentration

3) Their surface area

4) Whether or not a _______ is used

Words – activation, quicker, catalyst, temperature, collide

11/04/23

CatalystsCatalystsTask

Research and find out about two uses of catalysts in industry, including:

1) Why they are used

2) The disadvantages of each catalyst

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Catalyst SummaryCatalyst SummaryCatalysts are used to ____ __ a reaction to increase the rate at which a product is made or to make a process ________. They are not normally ___ __ in a reaction and they are reaction-specific (i.e. different reactions need _________ catalysts).

Words – different, speed up, used up, cheaper

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Rate of reaction graph v1Rate of reaction graph v1

Time taken for reaction to complete

Temperature/ concentration

Reaction takes a long time

here

Reaction is quicker

here

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Rate of reaction graph v2Rate of reaction graph v2Amount of product formed/ amount of reactant used up

Time

Slower reactionFast rate

of reaction here

Slower rate of reaction here due to reactants being used

up

Rate of reaction = amount of product formed/reactant used up

time

11/04/23ElectrolysisElectrolysis

++++

----

Positive electrode

Cu2+

Cu2+

Cu2+

Negative electrode

Cl-

Cl-

Cl-

Solution containing copper and

chloride ions

11/04/23

ElectrolysisElectrolysisElectrolysis is used to separate a metal from its compound.

= chloride ion

= copper ion

When we electrolysed copper chloride the _____ chloride ions moved to

the ______ electrode and the ______ copper ions moved to the ______

electrode – OPPOSITES ATTRACT!!!

11/04/23Electrolysis equationsElectrolysis equationsWe need to be able to write “half equations” to show what happens during electrolysis (e.g. for copper chloride):

2 2

2

At the negative electrode the positive ions GAIN electrons to

become neutral copper ATOMS. The half equation is:

Cu2+ + e- Cu

At the positive electrode the negative ions LOSE electrons to

become neutral chlorine MOLECULES. The half equation is:

Cl- - e- Cl2

11/04/23

Purifying CopperPurifying Copper

++++

----

Solution containing copper ions

Impure copper

Cu2+

Cu2+

Cu2+

Pure copper

At the positive electrode:

Cu(s) Cu2+(aq) + 2e-

At the negative electrode:

Cu2+(aq) + 2e- Cu(s)

11/04/23

Electrolysis of brineElectrolysis of brine

Positive electrode

Negative electrode

Sodium chloride (brine)

NaCl(aq)

Sodium hydroxide (NaOH(aq))

Sodium chloride (salt) is made of an alkali metal and a halogen. When it’s dissolved we call the solution “brine”, and we can electrolyse it to produce 3 things…

Chlorine gas (Cl2) Hydrogen gas (H2)

11/04/23Universal Indicator and the pH Universal Indicator and the pH scalescale

Strong acid Strong alkali

Neutral

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Universal Indicator is a mixture of liquids that will produce a range of colours to show how strong the acid or alkali is:

Stomach acid

Lemon juice

Water Soap Oven cleaner

Baking powder

An acid contains hydrogen ions, H+

An alkali contains hydroxide ions, OH-

11/04/23Neutralisation reactionsNeutralisation reactionsWhen acids and alkalis react together they will NEUTRALISE each other:

OHNa

Sodium hydroxide

ClH

Hydrochloric acid

The sodium “replaces” the hydrogen from HCl

ClNa

Sodium chloride

H2O

Water

General equation: H+(aq) + OH-

(aq) H2O(l)

11/04/23

Making saltsMaking saltsWhenever an acid and alkali neutralise each other we are left with a salt, like a chloride or a sulphate. Complete the following table:

Hydrochloric acid

Sulphuric acid Nitric acid

Sodium hydroxide

Sodium chloride + water

Potassium hydroxide

Potassium sulphate + water

Calcium hydroxide

Calcium nitrate + water

11/04/23

Making SaltsMaking SaltsSoluble salts can be made from acids by reacting them with:1) Metals, e.g.

Zn + 2HCl ZnCl2 + H2

2) Insoluble bases, e.g.

CuO + 2HCl CuCl2 + H20

3) Alkalis (alkali = a “soluble base”), e.g.

NaOH + HCl NaCl + H20Salts can be made from these solutions by crystallizing

them.

11/04/23

Ammonium saltsAmmonium salts

Guten tag again. When ammonia dissolves in water it produces an

alkaline solution:

NH3 + H20 NH4OH

This solution can be used to make fertilisers. Very useful!

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