The document provides an introduction to basic chemistry concepts including the composition of matter, elements, atoms, bonds, chemical reactions, and acids and bases. It explains that matter is made up of elements which are composed of atoms, and that chemical bonds between atoms are either ionic or covalent. Chemical reactions involve the rearrangement of atoms and transfer of electrons through oxidation and reduction.

1. Introduction to Chemistry
QBA Miguel A. Castro Ramírez

2. Composition of Matter
• Matter is anything that occupies
space and has mass.
• Mass is the quantity of matter an
object has.
• Mass and weight are different.
• Weight depends on the amount of
gravity.
• You would weigh less on the moon
than on earth but have the same
mass.
• http://www.exploratorium.edu/ronh/weight

3. What is matter?
air water
light darkness
smoke
human
cold
heat
sound
jello

4. Element
• An element is a pure substance that
cannot be broken down into simpler kinds
of matter.
• Each element has a different chemical
symbol.
• More than 100 elements have been
identified.
• More than 90% of the mass of living
things is composed of oxygen, carbon,
hydrogen and nitrogen

6. Atom
• An atom is the simplest part of an element that
retains the properties of that element.
• The properties of atoms determine how the
element will behave in nature.
• An atoms consists of three parts.
• The nucleus contains protons and neutrons.
• Electrons float around the outside of the
nucleus.
• The number of protons is called the atomic
number.
• Protons are charges positively, electrons are
negative and neutrons are neutral or zero
charge.

8. Atomic Particles
Name of Location Charge Related
Particle Info
Proton Nucleus + Measured
by atomic
number
Neutron Nucleus 0 Measured
by atomic
mass
Electron Outside - Helps
the with
nucleus bonding

9. Electrons
• Electrons are responsible for making
chemicals.
• Electrons are set in different layers
called energy levels.
• Each level can hold up to 8
electrons except the innermost level
which can only hold 2.

11. Compounds
• A compound is a pure substance made up of
two or more elements.
• A chemical formula shows what elements and
how many are in a compound.
• An atom is chemically stable when its outer shell
has 8 electrons with the exception of helium and
hydrogen.
• That is why elements bond together.
• When elements bond together they create a
chemical reaction which makes the atoms happy
and stable.

12. Covalent bonds
• Covalent bonds form when atoms
share one or more pairs of
electrons.
• This usually happens between
nonmetals.
• A molecule is formed when a
covalent bond is used.
• Examples are: water, carbon dioxide
and oxygen gas

15. Ionic Bonds
• Ionic bonds form when one atom
transfers electrons from itself to
another atom.
• When this occurs, an ion is formed.
• Ionic bonds usually happen between
a metal and a nonmetal.

17. Energy and Matter
• Energy is the ability to do work or
cause change
• Free energy is the energy in a
system available for work.
• There are three main states of
matter.
• Solid, liquid and gas.

18. Energy and Chemical
Reactions
• Living things undergo thousands of
chemical reactions as part of their
life processes.
• The reactants are shown on the left
side of the equation.
• The products are shown on the right
side.
• Reactants are converted to
products.
• Energy is required for the chemical
reaction to occur.

19. A chemical reaction must make
something totally different that has
different properties from when it
started.
You start with the reactants And you end with the products

20. When you make a
sandwich, what do you
do?

21. When you make a
sandwich, what do
you do?
Products
Reactants

22. How can you recognize a chemical
reaction?
Breaking glass
Ice pack Rusting car
Frying an egg
Burning a match
Boiling water
Shaking pop
Hand warmers
Chopping
Freezing veggies
water Cooking
Baking a cake
macaroni

24. Energy Transfer
• Chemical reactions that release energy
are called exergonic reactions.
• Chemical reactions that absorb energy
are called endergonic reactions.
• Both exergonic and endergonic reactions
require energy to start the process.
• This is called activation energy.
• Certain chemicals called catalysts, reduce
the amount of activation energy required.
• The reaction happens easier.
• One catalyst in the body is called an
enzyme.

26. Redox reactions
• Many chemicals reactions that help
transfer energy in living things involve the
transfer of electrons.
• These are called reduction-oxidation
reactions or redox reactions.
• In oxidation, a reactant loses one or more
electrons, making it a positive ion.
• In reduction, a reactant gains one or more
electrons making it more negative.
• There is always an atom that is oxidized
and an atom that is reduced.

27. Solutions
• A solution is a mixture in which one or more
substances is uniformly distributed in another
substance.
• A solution has two parts.
• The solute is the substance dissolved in the
solution.
• The solvent is the substance in which the solute
in dissolved.
• The concentration is the measurement of the
amount of solute dissolved in the solvent.
• A saturated solution is one in which no more
solute can dissolve.
• An aqueous solution are solutions in which water
is the solvent. These are very common.

28. Acids and Bases
• Dissociation is the breaking apart of
water.
• When water breaks, two things are made.
• The hydroxide ion is OH-
• The hydrodium ion is H3O+
• If the number of hydrodium ions is greater
than the number of hydroxide ions, the
solution is an acid.
• Sometimes hydrodium is just written H+
• If the number of hydroxide ions is greater
than the hydrodium ions, then the solution
is a base.

30. pH and Buffers
• pH is the scale for comparing the relative
concentrations of hydronium in a solution.
• The scale ranges from 0 to 14.
• The smaller the number, the more acidic a
solution is. The higher the number, the more
basic it is.
• For example, stomach acid has a pH of about 2.
Ammonia has a pH of about 12.
• Buffers are chemicals that neutralize acids and
bases in the body.
• Buffers help maintain good pH levels in the
body.

32. Which
Exchange or
have an
give/take
Atoms electrons electric
Charge
Which makes
Ionic bonds
and Ions

33. share
Molecules
electrons
Which makes
Covalent
bonds

34. Essential Questions
• How are particles arranged in an atom?
• How does an ionic bond differ from a covalent
bond?
• Why doesn’t Neon combine with elements very
often?
• What are the 3 state of matter?
• Explain how a catalyst affects a reaction.
• Why does a reduction always happen with an
oxidation?
• Describe the dissociation of water.
• What is neutral pH?
• What is a buffer? Why is it important to the
body?