Year 11 Chemistry

Module 1

Part 1

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Part 1Properties of Matter

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Properties and Structure of MatterInquiry question: How do the properties of substances help us to classify and separate them?

Atom

An atom is the smallest particle of an element that can take part in a chemical

reaction.

Molecule

A molecule is the smallest particle of a substance capable of separate existence.

List two examples of a molecule:

1.

2.

Mixture

If a sample of matter is not a pure substance, then we call it a mixture.

An impure substance is one substance contaminated with small amounts of

other substances. It is therefore a mixture.

Give two examples of a mixture.

1.

2.

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Separation of Mixtures

Separation of solids of different sizes.

For metal ores, crushing and sieving methods may be used.

The process of froth flotation is widely used for sulfide ores.

Magnetic properties are used to separate minerals in black sands, eg rutile and

ilmenite.

What is one element these minerals contain?

Homework: Briefly outline the process of ‘froth flotation’. Include a

diagram.

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Solids and liquids.

Centrifuging – used to separate small amounts of solids in suspension.

Filtration – used to separate insoluble solids from a liquid.

Dissolved solids in liquids.

Dissolved solids in liquids are solutions.

Solute is the substance dissolved

Solvent is the substance doing the dissolving

Evaporation – the solvent is evaporated (vapourised) until the solute becomes dry and

the soluble solid remains.

Crystallisation – the slow cooling of a hot saturated solution. Crystals will appear as the

compound is less soluble at a cooler temperature.

Solubility Rule: Solubility increase with increasing temperatures, (except for gases

where solubility decreases with an increase in temperature.)

Separating liquids.

Soluble (miscible) liquids

Soluble liquids are separated by the process of distillation.

Distillation uses the different boiling points of the liquids to separate them.

The following diagrams outline:

1. A simple distillation apparatus

2. A fractionating column for refining crude petroleum.

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Separating immiscible (do not mix) liquids.

A separating funnel is used to separate immiscible liquids such as oil and

water.

Separating gases in air.

Air is passed through filters to remove particulate matter.

Air is passed through a solution of sodium hydroxide to remove carbon

dioxide.

Water is removed as ice by cooling to -25C

The air is then compressed and cooled until it liquefies, -200C.

The liquid is allowed to boil and the different gases are collected in a

fractionating column.

Boiling points of various gases:

Nitrogen = -196C

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Argon = -186C

Oxygen= -183C

Homework:

Briefly outline the following separation techniques:

SedimentationDecantationSievingPaper Chromatography

explore homogeneous mixtures and heterogeneous mixtures through practical investigations:- using separation techniques based on physical properties (ACSCH026)- calculating percentage composition by weight of component elements and/or

compounds (ACSCH007)

Practicals

Sand and calcium carbonate

A suspension of calcium carbonate in water

Salt dissolved in water

Calcium sulfate, copper sulfate and water

An oil and water mixture

Alcohol and water mixture

The colours in a felt tip pen

Chemistry in Focus

Check your understanding 2.1, page 24 x 2.2

Check your understanding 2.2, page 30

Check your understanding 2.3, page 33

Chapter Review Questions p42

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● Investigating nomenclature of inorganic substances using International Union of Pure and Applied Chemistry (IUPAC) naming conventions.

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Review of Ions and Ion Formation.

Electronegativity

The Electronegativity of an element is the ability of an atom of the element to attract

electrons.

Ions:

An ion is an atom that has lost or gained an electron(s).

There are two types of ions:

1. Cation

A cation is an atom that has lost an electron(s).

Cations have a positive charge.

This positive charge comes from there being more protons (+ve) than there are

electrons (-ve).

For example:

The sodium ion.

The sodium atom has one electron in its’ outer shell.

(Note: Atoms are more stable with complete outer shells.)

Draw the structure of the sodium atom and sodium ion.

2. Anions

An anion is an atom that has gained an electron(s).

Anions have a negative charge.

Draw the structure of the fluorine atom and fluoride ion:

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In terms of electrostatics, opposites attract. Therefore, positive ions (cations) will attract

negative ions (anions).

When this attraction occurs, ionic compounds form.

Rules for Writing Formulas and Names of Inorganic Compounds

The following summary is based on the IUPAC rules for naming compounds. The

rules are applied universally across all countries.

To write the formula of a compound from its name, apply the following rules in the

order written.

The chemical formula shows the relative number of each type of atom present in a

substance using elemental symbols to represent atoms and subscripted numbers to

indicate the number of each type of atom.

For binary compounds (those containing two elements), the following rules should be

applied in order:

1. Apart from Hydrogen, the element further to the left in the Periodic Table appears first in the formula. Examples: NaCl; MgO

2. Hydrogen appears last except when the other element is from Group 16 or 17. Examples include: LiH, NH3, CH4, H2O and HF.

3. If both elements are in the same group the lower one appears first. Examples include: SiC, SO3.

4. If the compound is ionic, the cation is written first and the anion is written second. Examples: NaCl and MgCl2.

If the compound contains more than 1 element, the rules depend on whether it is ionic

or covalent:

Ionic compounds:

1. The order of the elements often follows the same rules as listed above for

binary compounds.

2. However, more commonly the formula is written to give an indication of the

chemistry or the structure. Examples include the inorganic acids such as

H2SO4, HNO3 and H3PO4 in which the replaceable hydrogen is written first.

3. By convention, compound names are written in lower case except where the

name begins a sentence.

4. There should be a single space between the two parts of the name.

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Non-metallic Binary CompoundsCommon Roots

  element full name rootAs arsenic arsenBr bromine bromC carbon carbCl chlorine chlorF fluorine fluorH hydrogen hydrI iodine iodN nitrogen nitrP phosphorus phosphS sulfur sulf

https://scilearn.sydney.edu.au/firstyear/videos/tutorials.cfm?video=ichem_inorganic_nomenclature

Valency

● The valency or valence of an element or compound is a measure of its combining

power when it takes part in a chemical reaction.

● In general the valency of an element relates to it Group number in the periodic

Table, i.e

- Sodium is in Group 1 and has a valency of +1.

- Magnesium is in-group 2 and has a valency of +2.

- Chlorine is in Group 7 and has a valency of –1.

Exceptions to this rule are the multi-valent elements:

Element Valencies

Copper Cu+ ; Cu2+

Iron Fe2+ ; Fe3+

Lead Pb2+ ; Pb4+

Tin Sn2+ ; Sn4+

Mercury Hg+ ; Hg2+

Zinc Zn2+

Silver Ag+

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Polyatomic Ions

Cations:

Ammonium - NH4+

Anions

Polyatomic Anion Formula

Sulfate SO42-

Sulfite SO32-

Nitrate NO3-

Nitrite NO2-

Carbonate CO32-

Hydroxide OH-

Phosphate PO43-

Note: The ending –ide refers the anion being and element only, (the exception being

Hydroxide).

Ionic Compounds:

Ionic compounds are named by putting the cation first, followed by the anion. For

example:

Sodium Chloride, NaCl

Magnesium Carbonate, MgCO3

Note: When ionic compounds form they must be electrically neutral.

Ionic compounds with multiple valencies:

1. Using roman numerals

When a cation has a multiple valency, the valency of the cation is shown by placing

roman numerals in brackets after the cation.

For example:

Iron oxide when iron has the valency of 2+

Iron(ii) oxide → Fe2O3

Tin chloride when tin has a valency of 4+

Tin(iv) Chloride = SnCl4

2. Using the suffixes –ous and –ic

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The suffix –ous refers to the lower valence cation, while the suffix –ic refers to the

higher valent state.e.g

Iron(ii) oxide – Ferrous oxide

Iron(iii) oxide – Ferric oxide

Naming Ionic Compounds

https://www.youtube.com/watch?v=URc75hoKGLY

Ionic compounds can also be formed by transposing valencies.

Take notes from class discussions.

Homework: Complete the following table.

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Ionic Compound Name Chemical Formula

Potassium Sulfate

PbCl4

Magnesium Hydroxide

CuO

Cupric Chloride

SnO2

Lithium Hydride

Na2SO4

Sodium Carbonate

Mg3(PO4)2

Check your understanding: 5.1, 5.2, 5.3, 5.4 page 94

● classify the elements based on their properties and position in the periodic table through their:– physical properties

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– chemical properties

● Classification of Elements and Review of the Periodic Table structure.

Inquiry question: Why are atoms of elements different from one another?

Atomic structure and atomic mass

1. The Atom revisited.

An atom is made up of electrons, protons and neutrons.

Protons and neutrons are in the nucleus of an atom.

Protons are positively charged, neutrons have no charge.

Electrons have a negative charge.

The Atomic number, Z, of an atom is the number of protons in the nucleus of that

element.

For example, Calcium has 20 protons in its nucleus and has the atomic number 20.

The atomic number also equals the number of electrons in a neutral atom.

The Mass Number, A, of an element is the number of protons plus neutrons of an

atom of that element. The mass number is sometimes called the nucleon number.

For example:

Calcium has 20 protons and 20 neutrons, so the mass number of calcium is 40.

The mass number and atomic number are represented as follows:

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A Mass Number X Element Z Atomic Number Therefore, Calcium would be represented as: 40 Ca 20

Relative Atomic Mass

Isotope: An isotope is an atom of an element that has the same number of protons but a

different number of neutrons. For example, Carbon has the following isotopes: 12, 13 and

14.

This means that Carbon 12 has 6 protons and 6 neutrons; Carbon 13 has 6 protons and

7 neutrons and Carbon 14 has 6 protons and 8 neutrons.

The mass that appears on a periodic table is the Relative Atomic Mass. It is the mass

of that element relative to the Carbon 12 atom.

For example:

The relative atomic mass of Calcium is 40.08. This means that the Calcium atom is

3.34 (40.08 / 12) times heavier than Carbon.

Also it is the ratio of the naturally occurring isotopes of that element.

For Example:

Chlorine has the naturally occurring isotopes 75% 35Cl and 25% 37Cl.

Therefore, the relative atomic mass of Chlorine is:

(0.75 x 35) + (0.25 x 37) = 35.5

Which indicates that a chlorine atom is 2.96 (35.5 / 12) times heavier than a carbon

atom.

The Periodic TableThe periodic table is divided into 3 sections:

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1. Metals2. Non-metals 3. Semi-metals4. An additional group is the Transition Metals - this is found within the metals.

1. Metals

Typical metals share the following physical properties:

Relatively high densities.

Good conductors of heat and electricity

Malleable and ductile.

Malleable: can be beaten into shape

Ductile: can be drawn into a wire

Have a shiny surface (Lustre)

Relatively high melting points

2. Non-Metals

State and form is variable

Usually not lustrous

Poor conductors of heat and electricity

Not malleable or ductile

Variable melting points

3. Semi-Metals

Also known as metalloids

Semi-metals have a wide range of properties which are a combination of the

properties of metals and non-metals.

4. Transition Metals

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The 38 elements in groups 3 through 12 of the periodic table are called

"transition metals".

As with all metals, the transition elements are both ductile and malleable, and

conduct electricity and heat.

The interesting thing about transition metals is that their valence electrons, or

the electrons they use to combine with other elements, are present in more than

one shell.

This is the reason why they often exhibit several common oxidation states

(valencies).

There are three noteworthy elements in the transition metals family. These

elements are iron, cobalt, and nickel, and they are the only elements known to

produce a magnetic field.

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