MLT 1101 CHEMISTRY

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MLT 1101CHEMISTRY

• TOPIC 1
• MATTER AND THE THEORY OF STATE MATTER

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• INTRODUCTION
• TO THE
• MATTER

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• Matter is anything that occupies space and has
  mass.
• Matter can classified into physical and chemical
  state.
• There are 4 physical states of matter
• 1) Gas or Vapor
• No fixed volume or shape - it conforms to the
  container.
• Can be compressed or expanded
• Move randomly at great speeds
• Can vibrate, rotate, translate have highest
  energy content

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• 2) Liquid
• Has a fixed volume - shape depends on its
  container.
• Cannot compressed.
• Particle can vibrate, rotate translate.
• 3) Solid
• Has a fixed shape and volume it is rigid
• Cannot compressed.
• Particles can vibrate rotate at fixed positions
• 4) Plasma
• is a substance similar to gas in which
  electrically neutral medium of positive and
  negative particles
• they generate electrical currents by charges.

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THEORY OF STATE MATTER

• Matter is made up of tiny and discrete particles.
  There are spaces between these particles.
• The particles may be atoms, molecules or ions.
• An atom is the smallest particle of an element
  that can participate in a chemical reaction.
• A molecules is a group of two or more atoms which
  are chemically bonded together.
• An ion is a positively-charged or
  negatively-charged particle.

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• Particles of Matter are constantly moving
  contain kinetic energy.
• Particles of Matter are held together by very
  strong electric forces
• Matter can be classified by its chemical
  constituent whch are elements and compounds.
• a) An elements is a substance that consists
  of only one type of atom.
• b) A compound is a substance that contains
  two or more elements that are chemically bonded
  together.

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• 5. Each substance has unique particles that are
  different from the particles of other substances
• 6. Temperature affects the speed of the
  particles.  The higher the temperature, the
  faster the speed of the particles.

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CLASSIFICATION OF MATTER
Matter Anything with mass and volume Matter Anything with mass and volume Matter Anything with mass and volume Matter Anything with mass and volume
Substance Matter with constant composition Substance Matter with constant composition Mixture Matter with variable composition Mixture Matter with variable composition
Element Substance made up of only one type of atom Compound Two or more elements that are chemically combined Heterogeneous MixtureMixtures that are made up of more than one phase Homogeneous MixturesAlso called solutions.  Mixtures that are made up of only one phase
Examples - gold, silver, carbon, oxygen and hydrogen Examples - water, carbon dioxide, sodium bicarbonate, carbon monoxide Examples - sand, soil, chicken soup, pizza, chocolate chip cookies. Examples - salt water, pure air, metal alloys, seltzer water.
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States of Matter
Solid Liquid Gas
Attractive force among particles Strong Fairly strong Very weak
Compressibility Incompressible Incompressible Easy to compress
Volume Fixed Fixed and similar to solid No fixed volume (occupies the whole container)
Particle movement Can only vibrate Free to move slowly Free to move quickly
Shape Definite No definite shape (Fill bottom of the container) No definite shape (Fill the whole container)
Kinetic energy Low Medium High
Particles arrangement
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Matter changes
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Sublimation
Boiling/ evaporation
Melting
Freezing
Condensation
LIQUID
SOLID
GAS
Sublimation
Heat energy absorbed
Heat energy released
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Heating curve
Melting point Temperature at which it
changes from solid to liquid state Boiling
point Temperature at which it changes from
liquid to gas state.
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During Heating

• When a solid is heated, the particles absorb heat
  energy.
• The particles vibrate faster and kinetic energy
  increase.
• The movement of particles is increase
• The force of attraction become weak

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Cooling curve
Freezing point Temperature at which it
changes from liquid to solid state Condensation
point Temperature at which it changes from gas
to liquid state
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During Cooling

• When a gas is cooled, the particles release the
  energy.
• The kinetic energy will decrease
• The movement of particles is decrease
• The force of attraction become strong

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PHYSICAL AND CHEMICAL CHANGES

• PHYSICAL CHANGES

• CHEMICAL CHANGES

• A change that alters the APPEARANCE of a material
  but does not make the material into another
  substance
• Physical changes are REVERSIBLE
• Examples tearing paper, chopping wood, molding
  clay, melting ice

• a change in matter that PRODUCES A NEW SUBSTANCE
• Signs that a chemical change has taken place
• bubbles appear
• precipitate forms
• color change
• light is emitted
• temperature change
• change in smell or taste

• Energy is ALWAYS involved during BOTH physical
  and chemical changes

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Subatomic particles of an atom

• Atoms are made up of three types of smaller
  particles, namely protons, neutrons and
  electrons. These particles are known as subatomic
  particles.
• The relative masses and charges of these three
  subatomic particles in table below.

SUBATOMIC PARTICLE SYMBOL RELATIVE MASS RELATIVE ELECTRIC CHARGE
PROTON P 1 1
NEUTRON n 1 0
ELECTRON e 0 (almost) -1
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Subatomic particles of an atom

• Protons and neutrons are found in the nucleus of
  an atom while electrons surround the nucleus.

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SYMBOLS OF ELEMENTS

• Each element is given a name and a symbol. Some
  examples of elements and their symbols are shown
  below.

ELEMENT SYMBOL ELEMENT SYMBOL
Hydrogen H Sodium Na
Helium He Magnesium Mg
Lithium Li Aluminium Al
Beryllium Be Silicon Si
Boron B Phosphorus P
Carbon C Sulphur S
Nitrogen N Chlorine Cl
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• Notice that
• Each symbols consists of one or two letters.
• For most elements, the letters used in their
  symbols take either the first letter or first and
  another letter of their names. Eg. Hydrogen, H
  neon, Ne and Magnesium, Mg.
• For some elements, the symbols come from Latin
  names such as natrium (Na) for sodium and kalium
  (K) for potassium.

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PROTON NUMBER NUCLEON NUMBER

• Proton number an elements is the number of
  protons in its atom.
• Since atoms are neutral, the proton number is
  also the number of electrons in the atom.
• Each elements has its own proton number.
• E.g
• sodium has a proton number of 11. Hence all atoms
  of sodium have 11 protons.
• Oxygen has a proton number of 8, so all oxygen
  atoms have 8 protons.

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• The nucleon number is also known as the mass
  number.
• The relative mass of an atom is almost the same
  as its nucleon number. The nucleon number is
  sometimes used as the approximate relative mass
  in calculations.
• Protons and neutrons are collectively called
  nucleons because protons and neutrons occupy the
  nucleus.

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• Nucleon number total number of protons and total
  number of neutrons in its atom.
• From definition,
• or

Nucleon number number of proton number of
neutrons
Number of neutrons nucleon number number of
proton
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• Remember the charge on each subatomic particle
  like this
• Protons are positive,
• Neutrons are neutral,
• so electrons must be negative.
• In a neutral atom,
• number of electrons number of protons

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ISOTOPES

• Isotopes are atoms of the same element with the
  same number of protons but different numbers of
  neutrons.

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• Isotopes of an element have the same
• (a) number of protons in an atom.
• (b) number of electrons in an atom.
• (c) electron arrangement.
• (d) chemical properties because they have the
  same electron arrangement.

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• Isotopes of an element have different
• (a) nucleon number.
• (b) number of neutrons in an atom.
• (c) physical properties (such as density,
  melting point and boiling point), though these
  different are very small.

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USES OF ISOTOPES

• There are 2 types of isotopes, namely the
  radioactive and the non-radioactive isotopes.
• Radioactive isotopes or radioisotopes produce
  harmful radiation.
• However, radioisotopes can have important uses if
  they are handled properly. They are used in
  medicine, industry, agriculture and general
  research.

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1) Medical use

• Gamma-rays emitted from cobalt-60 are used in
  radiotherapy for the treatment of cancer.
• Superficial cancers such as skin cancer can be
  treated by less penetrating radiation from
  phosphorus-32 or strontium-90.
• A heart pacemaker which contains plutonium-238 is
  used to regulate the heartbeats of patients with
  heart problems.
• Iodine-131 is used in the treatment of thyroid
  diseases.

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2) Agricultural uses

• The uptake of phosphate and the metabolism of
  phosphorus by plants can be studied using a
  phosphate fertiliser containing phosphorus-32.
• Radioactive tracer studies using carbon-14 have
  helped in the understanding of photosynthesis and
  protein synthesis.

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3) Industry uses

• Sodium-24 can be used to trace leaks in gas or
  oil pipes and ventilating systems.
• The gamma rays of cobalt-60 are passed through
  food to destroy bacteria which cause the food to
  spoil without changing the quality, flavour, or
  texture of the food.
• The radiation from krypton-85 can be used to
  control the thickness of plastic sheets in the
  industry.

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4) Power sources

• Uranium-235 is the most common fuel used in
  nuclear power stations.

5) Archaeological uses

• Carbon-14 can be used to estimate the age bone,
  wood or fossils by measuring the fraction of
  carbon-14 it contains.

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ELECTRONIC STRUCTURE OF AN ATOM

• Electrons are arranged around the nucleus in the
  shells of an atom.
• The shell of an atom are numbered 1, 2, 3 and so
  on, starting from the one closest to the nucleus.
• Each shell can occupy a certain number of
  electron.

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ELECTRONIC STRUCTURE OF AN ATOM
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FINDING THE ELECTRON ARRANGEMENT

• To write the electron arrangement of an atom,
  follow these steps
• STEPS 1 Find out the proton number of the atom.
  (can refer to the Periodic Table)
• STEPS 2 Find out the number of electrons of the
  atom. For a neutral atom, the number of electrons
  is the same as the number of protons.

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FINDING THE ELECTRON ARRANGEMENT

• STEPS 3 Arrange the electrons in shells.
  Electrons occupy the shell closest to the nucleus
  first. The electrons only start occupying a new
  shell when the previous one has been occupied.

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VALENCE ELECTRONS

• Valence electrons are found in the outermost
  occupied shell of an atom.
• They determine the chemical properties of the
  element

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VALENCE ELECTRONS

• For e.g
• the electron arrangement of a chlorine atom is
  2.8.7. There are 7 electrons in the outermost
  occupied shell of the chlorine atom. Therefore,
  the number of valence electrons in a chlorine
  atom is 7.

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Thank You
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Quiz!!
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• 1) How many states of matter are there?
• A) 1 B)2 C) 3 D)4
• ANS There are 4 states of matter. You will
  find solids, liquids, gases and plasmas.
• 2) Atoms in a liquid are farther apart than the
  atoms in a gas.
• A) true
• B) false
• ANS Atoms in a gas are actually farther
  apart than the atoms in a liquid. Solids are the
  densest state of matter (of solids liquids, and
  gases). Gases are the least dense and have atoms
  that are the most spread out.

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• 3) Which has the least energetic molecules?a)
  Solids b) Liquids c) Gases d) Plasmas
• Ans Solids have the least energetic molecules.
  Plasmas and gases have the most energetic atoms.
• 4) What force pulls liquids towards the
  ground?a) Pressure b) Temperature c) Gravity
  
• d) centrifugal
• Ans Gravity is the one force that pulls every
  object towards the surface of the Earth.

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• When a substance goes from being a solid to a
  liquid, it is a...a) chemical change b)
  Physical change
• Ans When a substance moves from one state to
  another, it is a physical change. Physical
  changes usually happen because you add or take
  away energy. If one substance combines with
  another to make a new compound... That is a
  chemical change.

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Study smart!!!