General information

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General information
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Dr. Kyriacos Kyriacou

• Biochemistry, BSc, UK, 1977
• Biochemistry, PhD, UK, 1982
• Spent 15 years in UK
• At Frederick since 1991

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Chemistry ACHM 111

• 4 ECTS , lecture and lab
• Lecture once a week
• Group 1 Mondays 600-930 PM
• Group 2 Tuesdays 600-930 PM
• Laboratory Later in the course

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Chemistry ACHM111

• Course assessment
• Course work 40
• 20 Mid Term Exams
• 10 Laboratory work
• 10 Quiz
• Final Exam 60
• Total 100

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Chemistry and Engineering
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Advice

• If you are worried about chemistry, dont get
  behind! Keep up with reading, homework etc
• If I seem to think you know more than you really
  do, let me know
• Get help if you need it (classmates, TAs, me..)
• Focus on understanding, not just on guessing what
  might be on exams

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Introduction

• Look at the nature as a whole can divide things
  into two main categories living things
• 
  non-living things
• Chemistry plays a vital role in helping us to
  understand the properties and behavior of all
  matter. All matter consists of particles and can
  be divided into three main classes
• solids
• Liquids
• Gases
• These are called the three states of matter and
  are sometimes referred to as phases. They can all
  be distinguished from one another by the
  following characteristics.

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Three states of matter

• In nature can divide things into two main
  categories living things ( animals, plants,
  humans)
• Non-living things ( all the rest)
• Chemistry plays a vital role in helping us to
  understand the properties and behavior of all
  matter
• Matter can be divided into
• Solids
• Liquids
• Gases
• Three states (phases) of matter
• 
  

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Solids

• Have a definite shape and offer resistance to any
  attempt to change that shape. Their volumes are
  hardly affected by changes in temperature and
  pressure

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Liquids

• Have no definite shape and take the shape of the
  container. However, they have definite surfaces
  which limit the amount of the space they occupy.
  Liquids can flow, meaning that they can change
  their shape under the influence of very small
  forces. Like solids, their volumes are slighltly
  affected by changes in temperature and pressure.

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Gases

• They are like liquids in that they have no
  definite shape and can flow. Unlike a liquid a
  gas has no bounding surface and will fill
  completely any container in which it is placed.
  The volume of gases are very much affected by
  even small changes in temperature and pressure.

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States of matter
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Three states of water
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States of matter
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Particles
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Solid state

• Particles of solids are held in place by strong
  electrostatic forces and are densely packed
  together. Particles of solids vibrate constantly
  due to their internal energy but they cannot move
  from one place to another.  Particles of solids
  possess only vibrational energy.

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LIQUID STATE

• Particles of liquids are kept together by forces
  of attraction that are weaker than those of solid
  particles.  Within the walls of the  container
  they can move from place to place bumping into
  the sides of the container and into other
  particles.  This type of energy is called
  translational    energy.  This energy gives a
  liquid  the ability to flow and be poured and to
  spread when a liquid is spilled.  Liquid
  particles also have vibrational energy.

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GAS STATE

• Particles of gases are "more rarefied" than
  either liquids or solids.  This means that the
  forces of attraction that hold them together are
  very weak and that the spaces between them are
  much larger than the spaces between solid and
  liquid particles. Particles of gases can move 
  from  place to place within a container bumping
  against the walls of  the container and against
  other particles. They rotate and vibrate at the
  same time.  Particles of gases have rotational,
  translational and vibrational energy.  This
  explains why they can escape from a container
  very easily. They can put pressure on the side of
  the container (example a balloon or a tire).

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Properties of solids, liquids and gases can be
summarized as follows
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Effect of pressure and temperature
A pure substance can be made to exist in any one
of the three states. States are
reversible. Vapour describes a gas that is
near its boiling point
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Sublimation

• Normally on heating solid -gt liquid -gt gas but
  have a few substances which on heating go from
  solid to gas without forming a liquid.
• e.g. Solid CO2 dry ice -gt gas
• Iodine (s) -gt Iodine ( g)
• Ammonium chloride

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Changes of state
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Types of change

• Two main types
• Physical changes
• Chemical changes

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Physical change

• Produces no new kind of matter
• It is generally reversible
• It is not accompanied by great heat change
• Produces no change of mass ( of the substances)
• Examples
• All normal changes of state melting,
  solidification, vaporization, liquefaction
  (condensation)
• Magnetization of iron
• Heating of a metal wire by electricity

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Chemical change

• Always produces a new kind of matter
• It is generally not easily reversible
• It is usually accompanied by considerable heat
  change
• Produces individual substances whose masses are
  different from those of the original individual
  substances e.g. if two substances, A and B, react
  chemically producing substances, C and D the
  masses of the latter will be different from the
  masses of A and B
• examples
• The burning of any substance in air
• The rusting of iron
• The slaking of lime
• Explosion of coal-gas or hydrogen with air

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How to differentiate between them

• In a physical change the particles remain in the
  original arrangements or more to arrangements
  which can easily be changed back to the original.
  No new combinations of particles are found. When
  a solid melts or boils the particles move further
  apart but they keep whatever pattern and
  composition they had at the start. The original
  materials are left unchanged.

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• II. In a chemical change the particles undergo
  internal rearrangement and new combinations are
  formed with new end often very different
  properties from the original substance.
• E.g. Hydrogen burns in oxygen to form water
• A rearrangement of atoms take place two
  hydrogen atoms combine with an oxygen atom to
  give a molecule of water. Properties of water are
  very different from properties of oxygen and
  hydrogen (e.g. melting point, boiling point,
  effect on metals)

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Evidence to decide between I and II

• Has a new substance been formed? Are the
  properties very different?
• Can the change be reversed easily?
• Is the energy change, heat, large or small?

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Electric heater
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Differences between physical and chemical changes
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Conservation of mass

• Important principle
• Matter can neither be created nor destroyed.
  In a chemical change there may be an apparent
  change in mass a gas may be trapped in the
  reaction or it may escape. However if all the
  reagents and all the products are weighed the
  total mass before the reaction is found to the
  equal the total mass after the reaction

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Fossil fuel
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Refinery